Editing St. Louis (section)

===Topography===
[[File:St Louis Rivers.png|thumb|Rivers in the St. Louis area]]
According to the [[United States Census Bureau]], St. Louis has a total area of {{convert|66|sqmi}}, of which {{convert|62|sqmi}} is land and {{convert|4.1|sqmi}} (6.2%) is water.<ref name="GR1">{{cite web|url=https://www.census.gov/geo/maps-data/data/docs/gazetteer/counties_list_29.txt|publisher=United States Census Bureau|access-date=November 20, 2014|date=August 22, 2012|title=2010 Census Gazetteer Files|url-status=dead|archive-url=https://web.archive.org/web/20131021170230/http://www.census.gov/geo/maps-data/data/docs/gazetteer/counties_list_29.txt|archive-date=October 21, 2013|df=mdy-all}}</ref> The city is built on [[Hill|bluffs]] and terraces that rise 100–200 feet above the western banks of the Mississippi River, in the [[Midwestern United States]] just south of the [[Missouri River|Missouri]]-Mississippi [[confluence]]. Much of the area is a fertile and gently rolling prairie that features low hills and broad, shallow valleys. Both the Mississippi River and the Missouri River have cut large valleys with wide flood plains.{{Citation needed|date=November 2024}}

[[Limestone]] and [[Dolomite (rock)|dolomite]] of the [[Mississippian age|Mississippian]] [[geologic time scale|epoch]] underlie the area, and parts of the city are [[karst]] in nature. This is particularly true of the area south of downtown, which has numerous sinkholes and caves. Most of the caves in the city have been sealed, but many springs are visible along the riverfront. Coal, brick [[clay]], and [[millerite]] ore were once mined in the city. The predominant surface rock, known as ''St. Louis limestone'', is used as [[dimension stone]] and rubble for construction.{{Citation needed|date=November 2024}}

Near the southern boundary of the city of St. Louis (separating it from [[St. Louis County, Missouri|St. Louis County]]) is the [[River des Peres]], practically the only river or stream within the city limits that is not entirely underground.<ref>[http://www.rftstl.com/2000-12-06/news/a-sewer-runs-through-it/ St. Louis – News – A Sewer Runs Through It<!-- Bot generated title -->] {{Webarchive|url=https://web.archive.org/web/20070311021411/http://www.rftstl.com/2000-12-06/news/a-sewer-runs-through-it/ |date=March 11, 2007}}.</ref> Most of River des Peres was confined to a channel or put underground in the 1920s and early 1930s. The lower section of the river was the site of some of the worst flooding of the [[Great Flood of 1993]].<ref>{{Cite web |last=US Department of Commerce |first=NOAA |title=The Great Flood of 1993 |url=https://www.weather.gov/lsx/1993_flood#:~:text=On%20August%201st,%201993,%20the%20Mississippi%20River,49.58%20feet,%20the%20highest%20stage%20ever%20recorded. |access-date=2025-02-09 |website=www.weather.gov |language=EN-US}}</ref>

The city's eastern boundary is the Mississippi River, which separates Missouri from Illinois. The Missouri River forms the northern line of St. Louis County, except for a few areas where the river has changed its course. The [[Meramec River]] forms most of its southern line.{{Citation needed|date=November 2024}}