U.S. Route 13 or U.S. Highway 13 (US 13) is a north–south United States Numbered Highway established in 1926 that runs for 518 miles (834 km) from Interstate 95 (I-95) just north of Fayetteville, North Carolina, to US 1 in the northeastern suburbs of Philadelphia, Pennsylvania, near Morrisville. In all, it traverses five states in the Atlantic coastal plain region. It follows the Atlantic coast more closely than does the main north–south U.S. Highway of the region, US 1. Due to this, its number is out of place on the general U.S. Highway numbering grid, as it should be running west of US 11 but does not. Its routing is largely rural, the notable exceptions being the Hampton Roads area in Virginia and the northern end of the highway in Delaware and Pennsylvania. It is also notable for being the main thoroughfare for the Delmarva Peninsula and carrying the Chesapeake Bay Bridge–Tunnel to it in Virginia.

U.S. Route 1 or U.S. Highway 1 (US 1) is a major north–south United States Numbered Highway that serves the East Coast of the United States. It runs 2,370 miles (3,810 km) from Key West, Florida, north to Fort Kent, Maine, at the Canadian border, making it the longest north–south road in the United States. US 1 is generally paralleled by Interstate 95 (I-95), though US 1 is significantly farther west and inland between Jacksonville, Florida, and Petersburg, Virginia, while I-95 is closer to the coastline. In contrast, US 1 in Maine is much closer to the coast than I-95, which runs farther inland than US 1. The route connects most of the major cities of the East Coast from the Southeastern United States to New England, including Miami, Jacksonville, Augusta, Raleigh, Richmond, Washington, D.C., Baltimore, Philadelphia, Newark, New York City, New Haven, Providence, Boston, and Portland.