Editing U.S. Route 1 (section)

===Mid-Atlantic===
{{main|U.S. Route 1 in Virginia|U.S. Route 1 in the District of Columbia|U.S. Route 1 in Maryland|U.S. Route 1 in Pennsylvania|U.S. Route 1 in New Jersey|U.S. Route 1 in New York}}

In the [[Mid-Atlantic (United States)|Mid-Atlantic]], US&nbsp;1 generally serves some of the [[Northeast megalopolis|most populated areas of the east coast]].  Through [[Virginia]], US&nbsp;1 is paralleled by Interstates: the remainder of [[Interstate 85|I-85]] to [[Petersburg, Virginia|Petersburg]], [[Interstate 95|I-95]] through [[Richmond, Virginia|Richmond]] and [[Fredericksburg, Virginia|Fredericksburg]] to [[Alexandria, Virginia|Alexandria]], and [[Interstate 395 (Virginia–District of Columbia)|I-395]] into [[Arlington County, Virginia|Arlington]]. In much of Virginia, US&nbsp;1 was called the [[Jefferson Davis Highway]] by state law, although there are exceptions. South of Petersburg, it is known as Boydton Plank Road. Through some of [[Fairfax County, Virginia|Fairfax County]] and Alexandria, it is called the Richmond Highway.<ref>{{Cite news|url=https://www.washingtonpost.com/local/dc-politics/a-plastic-straw-ban-and-a-confederate-name-change-new-laws-in-the-dc-region-in-2019/2018/12/31/60e4d954-0d1c-11e9-831f-3aa2c2be4cbd_story.html|title=A plastic straw ban and a Confederate name change: New laws in the D.C. region in 2019|last1=Nirappil|first1=Fenit|date=December 31, 2018|newspaper=Washington Post|access-date=January 3, 2019|last2=Hernandez|first2=Arelis R.|archive-date=January 3, 2019|archive-url=https://web.archive.org/web/20190103054831/https://www.washingtonpost.com/local/dc-politics/a-plastic-straw-ban-and-a-confederate-name-change-new-laws-in-the-dc-region-in-2019/2018/12/31/60e4d954-0d1c-11e9-831f-3aa2c2be4cbd_story.html|url-status=live}}</ref> In February 2021, Virginia renamed all remaining portions of the Jefferson Davis Highway in the state to Emancipation Highway beginning on January 1, 2022.<ref name=":0">{{Cite web|title=LIS > Bill Tracking > HB2075 > 2021 session|url=https://lis.virginia.gov/cgi-bin/legp604.exe?211+sum+HB2075|access-date=February 26, 2021|website=lis.virginia.gov|archive-date=February 10, 2021|archive-url=https://web.archive.org/web/20210210043922/https://lis.virginia.gov/cgi-bin/legp604.exe?211+sum+HB2075|url-status=live}}</ref><ref name=":2">{{Cite web|last=Thomas|first=Pat|title=Governor signs remaining bills from 2021 Special Session|date=March 31, 2021|url=https://www.whsv.com/2021/04/01/governor-signs-remaining-bills-from-2021-special-session/|access-date=April 3, 2021|location=Harrisonburg, Virginia|publisher=[[WHSV-TV]]|language=en|archive-date=April 1, 2021|archive-url=https://web.archive.org/web/20210401163057/https://www.whsv.com/2021/04/01/governor-signs-remaining-bills-from-2021-special-session/|url-status=live}}</ref>

US&nbsp;1 crosses the [[Potomac River]] with I-395 on the [[14th Street bridges]] and splits to follow mainly [[14th Street (Washington, D.C.)|14th Street]] and [[Rhode Island Avenue]] through the [[District of Columbia]]. US&nbsp;1 is at the minimum of three lanes (with alternate passing) from the North Carolina state line to Petersburg with occasional four-lane divided sections. North of Petersburg is a four-lane undivided roadway at the minimum to the DC line. The route of US&nbsp;1 from Petersburg to the state line is parallel with the [[Atlantic Seaboard Fall Line]]. From Petersburg onward, it is parallel with I-95. After exiting DC into [[Maryland]], US&nbsp;1 follows the Baltimore–Washington Boulevard, the first of several modern highways built along the [[Washington–Baltimore combined statistical area]] corridor; I-95 is the newest, after the [[Baltimore–Washington Parkway]]. US&nbsp;1 runs through the [[University of Maryland, College Park]], campus in [[College Park, Maryland]]. The route bypasses [[Downtown Baltimore]] on [[North Avenue (Baltimore)|North Avenue]] and exits the city to the northeast on Belair Road, gradually leaving the I-95 corridor, which passes through [[Wilmington, Delaware]], for a straighter path toward [[Philadelphia]]. Around and beyond [[Bel Air, Harford County, Maryland|Bel Air]], US&nbsp;1 is a two-lane road, crossing the [[Susquehanna River]] over the top of the [[Conowingo Dam]] before entering Pennsylvania. (Routed further north, US&nbsp;1 bypasses the state of [[Delaware]], unlike I-95.)<ref name=maps/>

The two-lane US&nbsp;1 becomes a four-lane [[Controlled-access highway|expressway]], officially known as the John H. Ware III Memorial Highway, after [[John H. Ware III|the Pennsylvania representative]], just after crossing into [[Pennsylvania]]. This bypass extends around [[Oxford, Pennsylvania|Oxford]] and [[Kennett Square, Pennsylvania|Kennett Square]], merging into the four-lane divided [[Baltimore Pike]] just beyond the latter. At [[Media, Pennsylvania|Media]], US&nbsp;1 again becomes a freeway—the Media Bypass—ending just beyond [[Interstate 476|I-476]]. After several name changes, the road becomes [[City Avenue]], the western city limits of [[Philadelphia]], at the end of which a short [[Concurrency (road)|overlap]] with [[Interstate 76 (Ohio–New Jersey)|I-76]] leads to the [[Roosevelt Expressway (Philadelphia)|Roosevelt Expressway]] and then the 12-lane [[Roosevelt Boulevard (Philadelphia)|Roosevelt Boulevard]] partly overlapping [[U.S. Route 13|US&nbsp;13]]. US&nbsp;1 again becomes a freeway after leaving the city, bypassing [[Penndel, Pennsylvania|Penndel]] and [[Morrisville, Bucks County, Pennsylvania|Morrisville]] and crossing the [[Delaware River]] into [[New Jersey]] on the [[Trenton–Morrisville Toll Bridge]].<ref name=maps/>

After crossing into [[New Jersey]] in Mercer County, US&nbsp;1 continues on the [[Trenton Freeway]] through the state capital of [[Trenton, New Jersey|Trenton]] and [[Lawrence Township, Mercer County, New Jersey|Lawrence Township]] as a four-lane freeway. As the freeway ends, the four-lane [[divided highway]] upgrades to six lanes north of [[Interstate 295 (Delaware–Pennsylvania)|I-295]] passing through the [[Penns Neck, New Jersey|Penns Neck]] section of [[West Windsor, New Jersey|West Windsor]]. Through Penns Neck is a series of traffic signals. The [[New Jersey Department of Transportation]] (NJDOT) is looking to revamp the highway through this area by replacing traffic signals with grade separations. The highway enters [[Middlesex County, New Jersey|Middlesex County]] through [[Plainsboro Township, New Jersey|Plainsboro Township]] and [[South Brunswick, New Jersey|South Brunswick]], where the highest point resides.<ref>{{Cite journal|last=Rosenthal|first=Harold|date=1983|title=Water tower in South Brunswick Township|url=https://rucore.libraries.rutgers.edu/rutgers-lib/43303/|journal=Rutgers University Community Repository|language=en|doi=10.7282/T3N58JK0|access-date=August 29, 2017|archive-date=August 30, 2017|archive-url=https://web.archive.org/web/20170830004531/https://rucore.libraries.rutgers.edu/rutgers-lib/43303/|url-status=live}}</ref> By Forrestal Village, the highway downgrades from six to four lanes until after Finnegans Lane in [[North Brunswick, New Jersey|North Brunswick]]. Northward, it continues through [[New Brunswick, New Jersey|New Brunswick]] as a short limited-access highway until the [[County Route 529 (New Jersey)|County Route&nbsp;529]] (CR&nbsp;529)/Plainfield Avenue traffic signal in [[Edison, New Jersey|Edison]]. Through Edison and [[Woodbridge Township, New Jersey|Woodbridge Township]], US&nbsp;1 has a mix of boulevard and limited-access segments and continues to do so after the [[U.S. Route 9 in New Jersey|US&nbsp;9]] juncture in the [[Avenel, New Jersey|Avenel]] section of Woodbridge. The [[U.S. Route 1/9|US&nbsp;1/9]] [[concurrency (road)|concurrency]] continues through the rest of the state. The six-lane divided highway remains through [[Rahway, New Jersey|Rahway]] in [[Union County, New Jersey|Union County]] and [[Elizabeth, New Jersey|Elizabeth]], until it reaches [[Newark Liberty International Airport]], where it becomes a dual carriageway freeway around downtown [[Newark, New Jersey|Newark]] in [[Essex County, New Jersey|Essex County]] with a 2–2–2–2 configuration. The historic [[Pulaski Skyway]] takes US&nbsp;1/9 into [[Jersey City, New Jersey|Jersey City]], and the route exits the freeway at the [[Tonnele Circle]] to head north into [[Bergen County, New Jersey|Bergen County]]. US&nbsp;1/9 turns onto [[U.S. Route 46|US&nbsp;46]] as a limited-access highway, and the three routes run northeast to the [[George Washington Bridge Plaza]], where they merge into I-95. US&nbsp;46 ends in the middle of the bridge, which crosses the [[Hudson River]] into [[New York (state)|New York]], and [[U.S. Route 9|US&nbsp;9]] exits just beyond onto [[Broadway (Manhattan)|Broadway]] in [[Manhattan]], but US&nbsp;1 stays with I-95 onto the [[Cross Bronx Expressway]], exiting in [[the Bronx]] onto Webster Avenue. Two turns take US&nbsp;1 via [[Fordham Road]] to Boston Road, which it follows northeast out of the city, becoming Boston Post Road in [[Westchester County, New York|Westchester County]], never straying far from I-95. From the Bronx to the state line, it is a local road with two lanes in each direction, except in [[Rye, New York|Rye]] where it has a single lane in each direction. As it enters [[Greenwich, Connecticut]], it continues as a two-lane local road.