US-1

U.S. Route 1
Route information
Length:	2,369 mi (3,813 km)
Existed:	1926 – present
Major junctions
South end:	SR 5 in Key West, FL
	I‑10 in Jacksonville, FL I‑16 near Swainsboro, GA I‑20 near Florence SC I‑40 in Cary, NC I‑85 near Petersburg, VA I‑64 in Richmond, VA I‑76 in Philadelphia, PA I‑87 in New York, NY I‑90 / I‑93 in Boston, MA I‑95 in Houlton, ME
North end:	Route 161 at the Fort Kent–Clair Border Crossing
Location
States:	Florida, Georgia, South Carolina, North Carolina, Virginia, District of Columbia, Maryland, Pennsylvania, New Jersey, New York, Connecticut, Rhode Island, Massachusetts, New Hampshire, Maine
Highway system
United States Numbered Highway System List Special Divided Replaced

U.S. Route 1 (US 1) is a major north–south U.S. Highway that serves the East Coast of the United States. It runs 2,369 miles (3,813 km), from Fort Kent, Maine, at the Canada–US border, south to Key West, Florida, making it the longest north-south road in the United States. US 1 is generally paralleled by Interstate 95 (I-95), though the former is significantly farther west (inland) between Jacksonville, Florida, and Petersburg, Virginia. The highway connects most of the major cities of the east coast, including Miami, Richmond, Washington, D.C., Baltimore, Philadelphia, New York City, and Boston, passing from the Southeastern United States to New England.

While US 1 is generally the easternmost of the main north–south U.S. Highways, part of US 9, US 13, US 15, US 17, US 21, occupy corridors closer to the ocean. When the road system was laid out in the 1920s, US 1 was mostly assigned to the existing Atlantic Highway, which followed the Fall Line between the Piedmont and the Atlantic Coastal Plain north of Augusta, Georgia. At the time, the highways farther east were of lower quality and did not serve the major population centers. Construction of the Interstate Highway system gradually changed the use and character of US 1, and I-95 became the major north–south East Coast highway.

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Wikipedia