Editing Black Diamond, Washington

{{Use mdy dates|date=July 2023}}
{{Infobox settlement
|official_name            = Black Diamond, Washington
|settlement_type          = [[City government in Washington (state)|City]]
|image_skyline            = Top Works at Mine 11, Black Diamond, ca 1915 (MOHAI 4229).jpg
|imagesize                = 
|image_caption            = Top Works at Mine 11, Black Diamond, ca. 1915.
|image_map                = King_County_Washington_Incorporated_and_Unincorporated_areas_Black_Diamond_Highlighted.svg
|mapsize                  = 250px
|map_caption              = Location of Black Diamond, Washington
<!-- Location ------>
|subdivision_type         = Country
|subdivision_name         = United States
|subdivision_type1        = [[U.S. state|State]]
|subdivision_name1        = [[Washington (state)|Washington]]
|subdivision_type2        = [[List of counties in Washington|County]]
|subdivision_name2        = [[King County, Washington|King]]
<!-- Government ---->
|government_footnotes     = <ref name=blackdiamondgov>{{cite web|title=Mayor & Council|url=https://www.blackdiamondwa.gov/mayor-council|publisher=City of Black Diamond|access-date=November 24, 2024}}</ref>
|government_type          = [[Mayor–council government|Mayor–council]]
|leader_title             = [[Mayor]]
|leader_name              = Carol Benson
|established_title        = Established
|established_date         = mid-1880s
|established_title2       = [[Municipal corporation|Incorporated]]
|established_date2        = February 19, 1959
<!-- Area ----->
|unit_pref                = Imperial
|area_footnotes           = <ref name="CenPopGazetteer2024">{{cite web|title=2024 U.S. Gazetteer Files|url=https://www2.census.gov/geo/docs/maps-data/data/gazetteer/2024_Gazetteer/2024_gaz_place_53.txt|publisher=United States Census Bureau|access-date=November 24, 2024}}</ref>
|area_total_km2           = 18.65
|area_land_km2            = 17.09
|area_water_km2           = 1.54
|area_total_sq_mi         = 7.19
|area_land_sq_mi          = 6.60
|area_water_sq_mi         = 0.60
<!-- Population ------>
|population_est           = 6602
|pop_est_as_of            = 2023
|pop_est_footnotes        = <ref name="USCensusEst2023"/>
|population_as_of         = [[2020 United States census|2020]]
|population_footnotes     = <ref name="2020 Census (City)"/>
|population_total         = 4697
|population_density_km2   = 386.29
|population_density_sq_mi = 1000.51
<!-- General information -->
|timezone               = [[Pacific Time Zone|Pacific (PST)]]
|utc_offset             = –8
|timezone_DST           = PDT
|utc_offset_DST         = –7
|elevation_footnotes    = <ref name=gnis/>
|elevation_ft           = 558
|coordinates            = {{coord|47|18|35|N|122|00|15|W|region:US-WA_type:city|display=inline}}
<!-- Area/postal codes and others ---->
|postal_code_type       = [[ZIP Code]]
|postal_code            = 98010
|area_code              = [[Area code 360|360]] and [[Area code 564|564]]
|blank_name             = [[Federal Information Processing Standard|FIPS code]]
|blank_info             = 53-06330
|blank1_name            = [[Geographic Names Information System|GNIS]] feature ID
|blank1_info            = 2409855<ref name=gnis>{{GNIS|2409855}}</ref>
|website                = {{URL|https://www.blackdiamondwa.gov|blackdiamondwa.gov}}
|footnotes              = 
}}

'''Black Diamond''' is a city in [[King County, Washington|King County]], [[Washington (state)|Washington]], United States. The population was 4,697 at the [[2020 United States census|2020 census]].<ref name="2020 Census (City)">{{cite web|title=Explore Census Data |url=https://data.census.gov/profile/Black_Diamond_city,_Washington?g=160XX00US5306330 |publisher=[[United States Census Bureau]] |access-date=November 24, 2024}}</ref> In 2023, with a 40.6% growth rate,<ref name="USCensusEst2023"/> Black Diamond was the fastest growing small city in King County.<ref name=":2">{{Cite web|title=Seattle's population dropped, but another King County city saw fastest growth in WA |date=May 26, 2022 |url=https://www.seattletimes.com/seattle-news/data/while-seattles-population-declined-another-king-county-city-saw-fastest-growth-in-wa/ |access-date=June 29, 2022 |website=The Seattle Times |language=en-US |archive-date=June 28, 2022 |archive-url=https://web.archive.org/web/20220628141930/https://www.seattletimes.com/seattle-news/data/while-seattles-population-declined-another-king-county-city-saw-fastest-growth-in-wa/ |url-status=live}}</ref>

==History==
===Founding===
Black Diamond was originally inhabited by the Bəqəlšuł, which is [[Lushootseed]] for "from a high point from which you can see", part of [[Coast Salish|Coast Salish people]]. The area was home to a grill trap and smokehouse, and the tribe fished from [[Lake Sawyer]].<ref>{{Cite book|last1=Hollenbeck |first1=Jan L. |title=A cultural resource overview: prehistory, ethnography and history : Mt. Baker-Snoqualmie National Forest |url=http://catalog.hathitrust.org/api/volumes/oclc/17744564.html |last2=Moss |first2=Madonna |last3=United States |last4=Forest Service |last5=Pacific Northwest Region |date=1987 |publisher=U.S. Dept. of Agriculture, Forest Service, Pacific Northwest Region |location=Portland, Oregon |language=English |oclc=892024380}}</ref><ref>{{Cite book|last=Ruby |first=Robert H. |title=A guide to the Indian tribes of the Pacific Northwest |url=https://www.worldcat.org/oclc/557404302 |date=2010 |publisher=University of Oklahoma Press |others=John A. Brown, Cary C. Collins, M. Dale Kinkade, Sean O'Neill |isbn=978-0-8061-4024-7 |edition=3rd |location=Norman |oclc=557404302}}</ref><ref>{{Cite book|last=Deloria Jr. |first=Vine |title=Indians of the Pacific Northwest : From the Coming of the White Man to the Present Day. |url=https://www.worldcat.org/oclc/820070401 |date=2012 |publisher=Fulcrum Publishing |isbn=978-1-68275-051-3 |location=Golden |oclc=820070401}}</ref>

Black Diamond was officially incorporated on February 19, 1959. The town's late 20th century population growth has been mostly as a commuter community for people with jobs in Seattle, [[Bellevue, Washington|Bellevue]], and suburban centers within the [[Seattle Metropolitan Area]].<ref>{{Cite web|last=McNichols |first=Joshua |title=A Smart Home Neighborhood: Residents Find It Enjoyably Convenient Or A Bit Creepy |url=https://www.npr.org/2019/11/09/777747209/a-smart-home-neighborhood-residents-find-it-enjoyably-convenient-or-a-bit-creepy |date=November 9, 2019 |access-date=November 11, 2019 |website=NPR News |language=en |archive-date=November 10, 2019 |archive-url=https://web.archive.org/web/20191110224204/https://www.npr.org/2019/11/09/777747209/a-smart-home-neighborhood-residents-find-it-enjoyably-convenient-or-a-bit-creepy |url-status=live}}</ref>

===Coal mining===
Beginning in the 1880s Black Diamond was a rural [[coal mining]] area, developed by the [[Black Diamond Coal Mining Company]] of [[California]], which owned and operated the mine.<ref name="Jbyer">The move of coal miners from Nortonville, California to Black Diamond, Washington Territory, 1885 by Jacqueline Byer Dial, 1980.</ref>  The original residents were largely composed of former workers, from the company's previous coal mining operation in [[Nortonville, California]], which primarily sold coal to the thriving new metropolis of [[San Francisco]].<ref name="olson">Black Diamond: Mining the Memories, edited by Diane and Cory Olson, 1988.</ref>  A combination of low quality coal from the Nortonville mines, water intrusion into the workings there, and the discovery and economical transport of higher-quality Washington coal to San Francisco spelled the demise of Nortonville in the early 1880s.<ref name="kishaba">The History of Nortonville, by Robert Kishaba, 1961.</ref> The town was home to around 3,500 people by the early 1900s, many of them European [[immigrants]]; most of the working men were involved in producing coal. This coal was transported to [[Seattle]] via the [[Pacific Coast Coal]] train. Before 1911, the miners were affiliated with the [[United Mine Workers of America]] (UMWA), but by March 1911 had left en masse to join the [[Industrial Workers of the World]] (IWW).<ref name="IWWYearbook1911">{{cite web|last=Bragg |first=Nick |title=IWW Yearbook 1911 |url=http://depts.washington.edu/iww/iwwyearbook1911.shtml |website=IWW History Project |publisher=[[University of Washington]] |access-date=April 20, 2016 |archive-url=https://web.archive.org/web/20160602022347/http://depts.washington.edu/iww/iwwyearbook1911.shtml |archive-date=June 2, 2016 |url-status=dead }}</ref><ref name="IW_1911_03_09">{{cite news |author=<!--No author listed.--> |publication-date=March 9, 1911 |title=A New Local |volume=2 |issue=51 |page=3 |newspaper=[[Industrial Worker]] |url=https://archive.org/details/v2n51-w103-mar-09-1911-IW}}</ref>

After [[World War I]], the town shut down the mine as it was no longer viable. A second mining boom spurred growth in the town in the early 1930s on the strength of multiple mining operations promoted by the Morris brothers through the Palmer Coking Coal Company.  Mining has continued until recently through the Pacific Coast Coal Company, formerly of San Francisco.{{Citation needed|date=January 2024}}

The main building of the Black Diamond Historical Museum is the former train station, which served the [[Seattle and Walla Walla Railroad]] 1884–1916 and the Pacific Coast Railway 1916–1951. Regular passenger service ended in 1925, but a train still brought men to the mine until 1931, and trains continued to haul coal and freight into the 1940s.{{cn|date=February 2025}}

===Planned growth via master planned developments (MPDs)===
In the 1990's, the first Black Diamond city planner (Jason Paulsen), seized an opportunity to create a comprehensive development plan for the City of Black Diamond that when completed, would fundamentally change what and how the City of Black Diamond would evolve into — the first set of plans being the Growth Management Act (GMA) Comprehensive Plan, which included the concept of Master Planned Developments (MPDs).<ref>{{Cite web|last=McNichols |first=Joshua |date=October 24, 2018 |title=The dream of Black Diamond's big development is an alternative to suburban sprawl |url=https://www.kuow.org/stories/dream-black-diamonds-big-development-alternative-suburban-sprawl |access-date=June 29, 2022 |website=www.kuow.org |language=en |archive-date=July 15, 2023 |archive-url=https://web.archive.org/web/20230715202719/https://www.kuow.org/stories/dream-black-diamonds-big-development-alternative-suburban-sprawl |url-status=live}}</ref><ref>{{Cite web|last=King County |date=October 9, 1996 |title=Ordinance No. 12535 |url=https://kingcounty.gov/~/media/depts/executive/performance-strategy-budget/regional-planning/Comprehensive-Plan/1996_Ordinance-12534.ashx?la=en |access-date=June 29, 2022 |website=kingcounty.gov |archive-date=January 29, 2023 |archive-url=https://web.archive.org/web/20230129182024/https://kingcounty.gov/~/media/depts/executive/performance-strategy-budget/regional-planning/Comprehensive-Plan/1996_Ordinance-12534.ashx?la=en |url-status=live}}</ref><ref>{{Cite web|title=Toward Responsible Dev. v. City of Black Diamond, No. 69418-9-I {{!}} Casetext Search + Citator |url=https://casetext.com/case/toward-responsible-dev-v-city-of-black-diamond#N196646 |access-date=June 29, 2022 |website=casetext.com |archive-date=June 21, 2022 |archive-url=https://web.archive.org/web/20220621165029/https://casetext.com/case/toward-responsible-dev-v-city-of-black-diamond/#N196646 |url-status=live}}</ref><ref>{{Cite web|last=Neuts |first=Dana |date=April 15, 2011 |title=Neighborhood of the week: Black Diamond is scenic, historic and quaint |url=https://www.seattletimes.com/business/real-estate/neighborhood-of-the-week-black-diamond-is-scenic-historic-and-quaint/ |access-date=June 29, 2022 |website=The Seattle Times |language=en-US |archive-date=June 29, 2022 |archive-url=https://web.archive.org/web/20220629210151/https://www.seattletimes.com/business/real-estate/neighborhood-of-the-week-black-diamond-is-scenic-historic-and-quaint/ |url-status=live}}</ref>

In 2008 {{convert|156|acres}} were purchased for the first MPD.<ref>{{Cite web|date=October 1, 2008 |title=Tentative sale of county land could bring big housing development $51 million deal for 'donut hole' |url=https://www.covingtonreporter.com/news/tentative-sale-of-county-land-could-bring-big-housing-development-51-million-deal-for-donut-hole/ |access-date=June 29, 2022 |website=Covington-Maple Valley Reporter |language=en-US |archive-date=July 15, 2023 |archive-url=https://web.archive.org/web/20230715202728/https://www.covingtonreporter.com/news/tentative-sale-of-county-land-could-bring-big-housing-development-51-million-deal-for-donut-hole/ |url-status=live }}</ref> In 2010 the first MPDs applications were filed with the City of Black Diamond.<ref name=":0">{{Cite web|title=YarrowBay Mitigation Agreement {{!}} Maple Valley WA |url=https://www.maplevalleywa.gov/city-government/city-council/yarrowbay-mitigation-agreement |access-date=June 29, 2022 |website=www.maplevalleywa.gov |language=en |archive-date=May 28, 2022 |archive-url=https://web.archive.org/web/20220528091453/https://www.maplevalleywa.gov/city-government/city-council/yarrowbay-mitigation-agreement |url-status=live }}</ref><ref>{{Cite web|last=City of Black Diamond |date=September 28, 2010 |title=Ordinance No. 10-946 |url=https://www.blackdiamondwa.gov/sites/g/files/vyhlif306/f/uploads/ordinance_no._10-946.pdf |access-date=June 29, 2022 |website=www.blackdiamondwa.gov |archive-date=June 21, 2022 |archive-url=https://web.archive.org/web/20220621201233/https://www.blackdiamondwa.gov/sites/g/files/vyhlif306/f/uploads/ordinance_no._10-946.pdf |url-status=live }}</ref>

====Legal action against first MPDs====
From 2010 through 2018 legal battles were fought delaying development of the first MPDs:

* In 2010 Toward Responsible Development filed a land use petition (LUPA) against the first two MPDs.<ref>{{Cite web|last=Box |first=Dennis |date=October 13, 2010 |title=Toward Responsible Development files appeal against YarrowBay developments in Black Diamond {{!}} Read Document |url=https://www.covingtonreporter.com/news/toward-responsible-development-files-appeal-against-yarrowbay-developments-in-black-diamond-read-document/ |access-date=June 29, 2022 |website=Covington-Maple Valley Reporter |language=en-US |archive-date=June 21, 2022 |archive-url=https://web.archive.org/web/20220621190505/https://www.covingtonreporter.com/news/toward-responsible-development-files-appeal-against-yarrowbay-developments-in-black-diamond-read-document/ |url-status=live }}</ref> 
* In 2012 King County Superior Court denied the LUPA Toward Responsible Development filed with the Court of Appeals.<ref>{{Cite web|last=Box |first=Dennis |date=December 12, 2013 |title=Groundbreaking work on YarrowBay's The Villages development begins {{!}} Black Diamond |url=https://www.covingtonreporter.com/news/groundbreaking-work-on-yarrowbays-the-villages-development-begins-black-diamond/ |access-date=June 29, 2022 |website=Covington-Maple Valley Reporter |language=en-US |archive-date=June 21, 2022 |archive-url=https://web.archive.org/web/20220621191900/https://www.covingtonreporter.com/news/groundbreaking-work-on-yarrowbays-the-villages-development-begins-black-diamond/ |url-status=live }}</ref>  
* In 2014 appeals Court Commissioner Masako Kanazawa ordered Toward Responsible Development to pay a total of $162,798, for attorney fees and costs, to YarrowBay and the City of Black Diamond.<ref>{{Cite web|last=Box |first=Dennis |date=October 1, 2014 |title=Attorney fees and costs awarded to YarrowBay and Black Diamond by Court of Appeals commissioner |url=https://www.covingtonreporter.com/news/attorney-fees-and-costs-awarded-to-yarrowbay-and-black-diamond-by-court-of-appeals-commissioner/ |access-date=June 29, 2022 |website=Covington-Maple Valley Reporter |language=en-US |archive-date=June 21, 2022 |archive-url=https://web.archive.org/web/20220621191900/https://www.covingtonreporter.com/news/attorney-fees-and-costs-awarded-to-yarrowbay-and-black-diamond-by-court-of-appeals-commissioner/ |url-status=live }}</ref> 
* In 2016 Oakpointe (formerly YarrowBay) sued three City of Black Diamond Council members who opposed the MPDs.<ref>{{Cite web|date=December 2, 2016 |title=Developer sues Black Diamond council members who oppose his project |url=https://www.seattletimes.com/business/real-estate/developer-sues-black-diamond-council-members-who-oppose-development/ |access-date=June 29, 2022 |website=The Seattle Times |language=en-US |archive-date=April 6, 2023 |archive-url=https://web.archive.org/web/20230406200830/https://www.seattletimes.com/business/real-estate/developer-sues-black-diamond-council-members-who-oppose-development/ |url-status=live }}</ref>  
* In 2017 Black Diamond council files suit against the mayor.<ref>{{Cite web|last=Miller-Still |first=Ray |date=November 1, 2017 |title=Black Diamond council files suit against mayor; Oakpointe files to intervene |url=https://www.covingtonreporter.com/news/black-diamond-council-files-suit-against-mayor-oakpointe-files-to-intervene/ |access-date=June 29, 2022 |website=Covington-Maple Valley Reporter |language=en-US |archive-date=June 21, 2022 |archive-url=https://web.archive.org/web/20220621201159/https://www.covingtonreporter.com/news/black-diamond-council-files-suit-against-mayor-oakpointe-files-to-intervene/ |url-status=live }}</ref> 
* In 2018 Black Diamond / Oakpointe settle lawsuit.<ref>{{Cite web|last=Kear |first=Kathleen |date=February 13, 2018 |title=Black Diamond /Oakpointe OPMA Lawsuit Settles |url=https://voiceofthevalley.com/2018/02/12/black-diamond-oakpointe-opma-lawsuit-settles/ |access-date=June 29, 2022 |website=VOICE of the Valley |language=en-US |archive-date=July 15, 2023 |archive-url=https://web.archive.org/web/20230715202719/https://voiceofthevalley.com/2018/02/12/black-diamond-oakpointe-opma-lawsuit-settles/ |url-status=live }}</ref>

====First MPDs====
The first two MPDs comprised 6,050 single and multi-family residences, 1.1 million square feet of [[Commercial area|commercial]]/office/[[retail]] space and were estimated to 15,000 new residents to the City of Black Diamond;<ref name=":0" /> which would increase the population of the city by 3.6 times its size at the time (2010 population estimate of [[2010 United States census|4,151]]).<ref name=":0" />

In December 2013 development started on the first MPD;<ref>{{Cite web|last=Box |first=Dennis |date=December 12, 2013 |title=Groundbreaking work on YarrowBay's The Villages development begins {{!}} Black Diamond |url=https://www.covingtonreporter.com/news/groundbreaking-work-on-yarrowbays-the-villages-development-begins-black-diamond/ |access-date=June 29, 2022 |website=Covington-Maple Valley Reporter |language=en-US |archive-date=June 21, 2022 |archive-url=https://web.archive.org/web/20220621191900/https://www.covingtonreporter.com/news/groundbreaking-work-on-yarrowbays-the-villages-development-begins-black-diamond/ |url-status=live }}</ref> known as Ten Trails.<ref>{{Cite web|last=Registry |first=The |date=January 11, 2018 |title=136 Acres of Undeveloped Land in Black Diamond, Washington, Sell for $18.6MM |url=http://news.theregistryps.com/136-acres-undeveloped-land-black-diamond-washington-sell-18-6mm/ |access-date=June 29, 2022 |website=The Registry |language=en-US |archive-date=August 11, 2022 |archive-url=https://web.archive.org/web/20220811154259/https://news.theregistryps.com/136-acres-undeveloped-land-black-diamond-washington-sell-18-6mm/ |url-status=live }}</ref> In 2019 the first family moves into Ten Trails.<ref>{{Cite web|last=Miller-Still |first=Ray |date=July 19, 2018 |title=First family officially moves into Ten Trails |url=https://www.covingtonreporter.com/news/first-family-officially-moves-into-ten-trails/ |access-date=June 29, 2022 |website=Covington-Maple Valley Reporter |language=en-US |archive-date=July 2, 2022 |archive-url=https://web.archive.org/web/20220702042819/https://www.covingtonreporter.com/news/first-family-officially-moves-into-ten-trails/ |url-status=live }}</ref>

In 2021, with a 21% growth rate,<ref name="USCensusEst2023"/> Black Diamond was the fastest growing small city in King County.<ref name=":2" />

In March 2022, 845 households were occupied in Ten Trails (722 residential homes, 76 apartment units, and 47 rental homes).<ref name=":3">{{Cite web|last=City of Black Diamond |date=March 15, 2022 |title=2022 Update by Mayor Carol Benson |url=https://www.blackdiamondwa.gov/sites/g/files/vyhlif306/f/uploads/state_of_the_city.pdf |access-date=June 29, 2022 |website=www.blackdiamondwa.gov |archive-date=June 21, 2022 |archive-url=https://web.archive.org/web/20220621215005/https://www.blackdiamondwa.gov/sites/g/files/vyhlif306/f/uploads/state_of_the_city.pdf |url-status=live }}</ref>

Using [[King County, Washington|King County]]'s 2020 Person's per household rate of 2.43,<ref name=":4">{{Cite web|title=U.S. Census Bureau QuickFacts: King County, Washington |url=https://www.census.gov/quickfacts/kingcountywashington |access-date=June 30, 2022 |website=www.census.gov |language=en |archive-date=August 8, 2022 |archive-url=https://web.archive.org/web/20220808083819/https://www.census.gov/quickfacts/kingcountywashington |url-status=live }}</ref> 845 households being occupied in Ten Trails in March 2022,<ref name=":3" /> the estimated population of Black Diamond in 2022 being 6,336,<ref name="USCensusEst2023"/> concludes the estimated population living in Ten Trails in March 2022 being 2,053 (845<ref name=":3" /> * 2.43<ref name=":4" />); which roughly equates to 79% ( 2,053 / 6,336<ref name="USCensusEst2023"/>) of the population of Black Diamond living in the first MPD (Ten Trails) during March 2022.

[[File:Black Diamond Cemetery tomb 01.jpg|thumb|Many early residents of Black Diamond came from Italy; this is one of many grave markers in the Black Diamond Cemetery with an Italian-language inscription. The cemetery is listed on the [[National Register of Historic Places]].]]

==Geography==
According to the [[United States Census Bureau]], the city has a total area of {{convert|7.193|sqmi|sqkm|2}}, of which {{convert|6.598|sqmi|sqkm|2}} is land and {{convert|0.595|sqmi|sqkm|2}} is water.<ref name="CenPopGazetteer2024"/>

There are several lakes in and just outside city limits, including [[Horseshoe Lake (King County, Washington)|Horseshoe Lake]].

==Demographics==
{{US Census population
|align=left
|1890= 561
|1960= 1026
|1970= 1160
|1980= 1170
|1990= 1422
|2000= 3970
|2010= 4151
|2020= 4697
|estyear=2023
|estimate=6602
|estref=<ref name="USCensusEst2023">{{cite web|url=https://www.census.gov/data/tables/time-series/demo/popest/2020s-total-cities-and-towns.html |date=November 23, 2024|title=City and Town Population Totals: 2020–2023|publisher=United States Census Bureau|accessdate=November 24, 2024}}</ref>
|align-fn=center
|footnote=U.S. Decennial Census<ref>{{cite web|url=https://www.census.gov/programs-surveys/decennial-census.html|title=Census of Population and Housing|publisher=United States Census Bureau|accessdate=June 4, 2015}}</ref><br>2020 Census<ref name="2020 Census (City)"/>
}}

As of the 2022 [[American Community Survey]], there are 2,072 estimated households in Black Diamond with an average of 2.56 persons per household. The city has a median household income of $134,076 and the per capita income was $62,896. Approximately 0.9% of the city's population lives at or below the poverty line. Black Diamond has an estimated 73.0% employment rate, with 52.5% of the population holding a bachelor's degree or higher and 98.5% holding a high school diploma.<ref>{{Cite web|title=U.S. Census Bureau QuickFacts: Black Diamond city, Washington|url=https://www.census.gov/quickfacts/fact/table/blackdiamond/PST045223|access-date=November 24, 2024|website=www.census.gov|language=en}}</ref>

The top five reported ancestries (people were allowed to report up to two ancestries, thus the figures will generally add to more than 100%) were English (90.9%), Spanish (3.8%), Indo-European (1.9%), Asian and Pacific Islander (3.4%), and Other (0.0%).

The median age in the city was 40.0 years.

===2020 census===
{| class="wikitable"
|+'''Black Diamond, Washington – racial and ethnic composition'''<br><small>{{nobold|''Note: the US Census treats Hispanic/Latino as an ethnic category. This table excludes Latinos from the racial categories and assigns them to a separate category. Hispanics/Latinos may be of any race.''}}</small>
! Race / ethnicity <small>(''NH = non-Hispanic'')</small>
! Pop. 2000<ref name=2000CensusP004>{{Cite web|title=P004: Hispanic or Latino, and Not Hispanic or Latino by Race – 2000: DEC Summary File 1 – Black Diamond city, Washington|url=https://data.census.gov/table/DECENNIALSF12000.P004?g=160XX00US5306330|publisher=[[United States Census Bureau]]|access-date=November 24, 2024}}</ref>
! Pop. 2010<ref name=2010CensusP2>{{Cite web|title=P2: Hispanic or Latino, and Not Hispanic or Latino by Race – 2010: DEC Redistricting Data (PL 94-171) – Black Diamond city, Washington|url=https://data.census.gov/table?q=p2&g=160XX00US5306330&tid=DECENNIALPL2010.P2|publisher=[[United States Census Bureau]]|access-date=November 24, 2024}}</ref>
! {{partial|Pop. 2020}}<ref name=2020CensusP2>{{Cite web|title=P2: Hispanic or Latino, and Not Hispanic or Latino by Race – 2020: DEC Redistricting Data (PL 94-171) – Black Diamond city, Washington|url=https://data.census.gov/cedsci/table?q=p2&g=160XX00US5306330&tid=DECENNIALPL2020.P2|publisher=[[United States Census Bureau]]|access-date=November 24, 2024}}</ref>
! % 2000
! % 2010
! {{partial|% 2020}}
|-
| [[Non-Hispanic or Latino whites|White]] alone (NH)
| 3,650
| 3,700
| style='background: #ffffe6; |3,655
| 91.94%
| 89.14%
| style='background: #ffffe6; |77.82%
|-
| [[Non-Hispanic or Latino African Americans|Black or African American]] alone (NH)
| 3
| 47
| style='background: #ffffe6; |34
| 0.08%
| 1.13%
| style='background: #ffffe6; |0.72%
|-
| [[Native Americans in the United States|Native American]] or [[Alaska Native]] alone (NH)
| 57
| 29
| style='background: #ffffe6; |26
| 1.44%
| 0.70%
| style='background: #ffffe6; |0.55%
|-
| [[Asian Americans|Asian]] alone (NH)
| 40
| 50
| style='background: #ffffe6; |129
| 1.01%
| 1.20%
| style='background: #ffffe6; |2.75%
|-
| [[Pacific Islander Americans|Pacific Islander]] alone (NH)
| 1
| 12
| style='background: #ffffe6; |15
| 0.03%
| 0.29%
| style='background: #ffffe6; |0.32%
|-
| [[Race and ethnicity in the United States census|Other race]] alone (NH)
| 10
| 4
| style='background: #ffffe6; |27
| 0.25%
| 0.10%
| style='background: #ffffe6; |0.57%
|-
| [[Multiracial Americans|Mixed race or multiracial]] (NH)
| 102
| 116
| style='background: #ffffe6; |314
| 2.57%
| 2.79%
| style='background: #ffffe6; |6.69%
|-
| [[Hispanic and Latino Americans|Hispanic or Latino]] (any race)
| 107
| 193
| style='background: #ffffe6; |497
| 2.70%
| 4.65%
| style='background: #ffffe6; |10.58%
|-
| '''Total'''
| '''3,970'''
| '''4,151'''
| style='background: #ffffe6; |'''4,697'''
| '''100.00%'''
| '''100.00%'''
| style='background: #ffffe6; |'''100.00%'''
|}
As of the [[2020 United States census|2020 census]], there were 4,697 people, 1,729 households, and 1,345 families residing in the city.<ref>{{Cite web|title=US Census Bureau, Table P16: Household Type |url=https://data.census.gov/table?q=Black%20Diamond%20city,%20Washington%20p16&y=2020 |access-date=November 24, 2024 |publisher=United States Census Bureau}}</ref> The [[population density]] was {{convert|717.1|PD/sqmi|PD/km2|1}}. There were 1,841 housing units at an average density of {{convert|281.1|/sqmi|/km2|1}}. The racial makeup of the city was 79.39% [[White (U.S. Census)|White]], 0.75% [[African American (U.S. Census)|African American]], 0.83% [[Native American (U.S. Census)|Native American]], 2.83% [[Asian (U.S. Census)|Asian]], 0.36% [[Race (U.S. Census)|Pacific Islander]], 5.94% from some other races and 9.90% from two or more races. [[Hispanic and Latino Americans|Hispanic or Latino]] people of any race were 10.58% of the population.<ref>{{Cite web|title=How many people live in Black Diamond city, Washington |url=https://data.usatoday.com/census/total-population/total-population-change/black-diamond-city-washington/160-5306330/ |access-date=November 24, 2024 |publisher=USA Today}}</ref> 24.4% of residents were under the age of 18, 7.0% were under 5 years of age, and 12.9% were 65 and older. The gender makeup of the city was 45.4% female.

===2010 census===
As of the [[2010 United States census|2010 census]], there were 4,151 people, 1,546 households, and 1,157 families living in the city. The population density was {{convert|690.1|PD/sqmi|PD/km2|1}}. There were 1,685 housing units at an average density of {{convert|280.4|/sqmi|/km2|1}}. The racial makeup of the city was 91.95% [[White (U.S. Census)|White]], 1.16% [[African American (U.S. Census)|African American]], 0.75% [[Native American (U.S. Census)|Native American]], 1.20% [[Asian (U.S. Census)|Asian]], 0.29% [[Race (U.S. Census)|Pacific Islander]], 1.30% from some other races and 3.35% from two or more races. [[Hispanic and Latino Americans|Hispanic or Latino]] people of any race were 4.65% of the population.

There were 1,546 households, of which 37.5% had children under the age of 18 living with them, 62.0% were [[Marriage|married couples]] living together, 8.6% had a female householder with no husband present, 4.3% had a male householder with no wife present, and 25.2% were non-families. 17.9% of all households were made up of individuals, and 6.1% had someone living alone who was 65 years of age or older. The average household size was 2.68 and the average family size was 3.05.

The median age in the city was 40.4 years. 25.2% of residents were under the age of 18; 7% were between the ages of 18 and 24; 25.7% were from 25 to 44; 32.1% were from 45 to 64; and 10% were 65 years of age or older. The gender makeup of the city was 49.8% male and 50.2% female.

===2000 census===
As of the [[2000 United States census|2000 census]], there were 3,970 people, 1,456 households, and 1,131 families living in the city. The [[population density]] was {{convert|739.5|PD/sqmi|PD/km2|1}}. There were 1,538 housing units at an average density of {{convert|286.5|/sqmi|/km2|1}}. The racial makeup of the city was 93.43% [[White (U.S. Census)|White]], 0.08% [[African American (U.S. Census)|African American]], 1.56% [[Native American (U.S. Census)|Native American]], 1.01% [[Asian (U.S. Census)|Asian]], 0.05% [[Race (U.S. Census)|Pacific Islander]], 0.88% from some other races and 3.00% from two or more races. [[Hispanic and Latino Americans|Hispanic or Latino]] people of any race were 2.70% of the population.

The top four reported ancestries were 16.8% were of [[Germans|German]], 13.2% [[Irish people|Irish]], 8.5% [[English people|English]] and 7.4% [[Norwegians|Norwegian]].

There were 1,456 households, out of which 41.2% had children under the age of 18 living with them, 65.2% were [[Marriage|married couples]] living together, 8.3% had a female householder with no husband present, and 22.3% were non-families. 17.2% of all households were made up of individuals, and 6.0% had someone living alone who was 65 years of age or older. The average household size was 2.73 and the average family size was 3.08.

In the city the population was spread out, with 28.5% under the age of 18, 6.2% from 18 to 24, 34.1% from 25 to 44, 22.9% from 45 to 64, and 8.3% who were 65 years of age or older. The median age was 36 years. For every 100 females, there were 103.6 males. For every 100 females age 18 and over, there were 101.6 males.

The median income for a household in the city was $67,092, and the median income for a family was $72,981. Males had a median income of $51,792 versus $31,932 for females. The [[per capita income]] for the city was $26,936. About 0.8% of families and 0.9% of the population were below the [[Poverty threshold|poverty line]], including 0.9% of those under age 18 and none of those age 65 or over.

==City landmarks==
The City of Black Diamond has designated the following landmarks:
{|class="wikitable"
|-
! Landmark
! Built
! Listed
! Address
! Photo
|-
| [[Black Diamond Depot]]<ref name=landmarks>{{cite web |title=King County and City Landmarks List |url=https://kingcounty.gov/~/media/services/home-property/historic-preservation/documents/resources/T06_KCLandmarkList.ashx?la=en |page=5 |website=www.kingcounty.gov/ |publisher=King County, Washington |date=November 2021 |access-date=January 16, 2024}}</ref> || 1886 || 2020 || 32627 Railroad Avenue || 
|-
| [[Black Diamond Cemetery]]<ref name=landmarks/> || c. 1880 || 2000 || Cemetery Hill Road || [[File:Black Diamond Cemetery 04.jpg|center|75px]]
|-
| [[Black Diamond Miners' Cabin]]<ref name=landmarks/> || c. 1882 || 1995 || 24311 Morgan Street || 
|-
| [[Luigi & Aurora Pagani House]]<ref name=landmarks/> || c. 1896 || 2001 || 32901 Merino Street || [[File:Black Diamond, WA - Luigi & Aurora Pagani House 01.jpg|100 px]]
|}

==Government and politics==
{| class="wikitable" style="float:right; font-size:95%;"
|+ Presidential Elections Results<ref>{{Cite web |title=King County Elections |url=http://www.kingcounty.gov/depts/elections/elections/past-elections.aspx |access-date=November 28, 2020 |archive-date=December 2, 2020 |archive-url=https://web.archive.org/web/20201202103033/https://www.kingcounty.gov/depts/elections/elections/past-elections.aspx |url-status=live}}</ref>
|- bgcolor=lightgrey
! Year
! [[Republican Party (United States)|Republican]]
! [[Democratic Party (United States)|Democratic]]
! [[Third Party (United States)|Third Parties]]
|-
| style="text-align:center; {{Party shading/Republican}}|'''[[2020 United States presidential election in Washington (state)|2020]]'''
| style="text-align:center; {{Party shading/Republican}}|'''50.54%''' ''1,635''
| style="text-align:center; {{Party shading/Democratic}}|46.52% ''1,505''
| style="text-align:center; background:honeyDew;"|2.94% ''95''
|}
Black Diamond remains one of the few right-leaning or Republican areas in King County. While [[Donald Trump]] carried the city twice, he did so both times by small margins.

==Notable people==
The town was home to folk musician [[Brandi Carlile]].<ref>{{Cite web |last=Scanlon |first=Tom |title=Maple Valley singer Brandi Carlile getting nationwide buzz |url=https://www.seattletimes.com/entertainment/maple-valley-singer-brandi-carlile-getting-nationwide-buzz/ |website=www.seattletimes.com |publisher=[[The Seattle Times]] |language=en-US |date=July 12, 2005 |access-date=April 6, 2022 |archive-date=April 6, 2022 |archive-url=https://web.archive.org/web/20220406003220/https://www.seattletimes.com/entertainment/maple-valley-singer-brandi-carlile-getting-nationwide-buzz/ |url-status=live }}</ref> The minor-league baseball star [[Edo Vanni]] was born at Black Diamond in 1918.<ref>{{Cite news |last=Raley |first=Dan |title=Edo Vanni, 1918-2007: As player, manager, promoter, he was '100 percent baseball' |url=https://www.seattlepi.com/sports/baseball/article/Edo-Vanni-1918-2007-As-player-manager-1235888.php |website=www.seattlepi.com |publisher=[[Seattle Post-Intelligencer]] |language=en-US |date=May 1, 2007 |access-date=April 6, 2022 |archive-date=April 6, 2022 |archive-url=https://web.archive.org/web/20220406003215/https://www.seattlepi.com/sports/baseball/article/Edo-Vanni-1918-2007-As-player-manager-1235888.php |url-status=live}}</ref>

==References==
{{reflist}}

==External links==
{{Commons category|Black Diamond, Washington}}
* [https://www.blackdiamondwa.gov/ City of Black Diamond – official website]
* [https://www.historylink.org/File/460 History of Black Diamond] at [[HistoryLink]]

{{King County, Washington}}
{{Washington}}

{{authority control}}

[[Category:Cities in King County, Washington]]
[[Category:Mining communities in Washington (state)]]
[[Category:1959 establishments in Washington (state)]]
[[Category:Company towns in Washington (state)]]
[[Category:Cities in Washington (state)]]