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.

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.

However, it has been extended many times, connecting to the mainland via ferry service and eventually reaching North Carolina.

The entire route on the Delmarva Peninsula, except for a few sections in Accomack County, Virginia, has been dualized fully with four lanes, and further upgrades continue, such as a freeway section around the east side of Salisbury, Maryland.

It passes over I-40 without an interchange; access is provided via US 701 or North Carolina Highway 50 (NC 50).

Between Dover and Wilmington in New Castle County, US 13 is paralleled by the Delaware Route 1 (DE 1) freeway, portions of which are a toll road.

Although US 13 was signed in most northern states by the late 1920s, it would not reach North Carolina until the early 1950s.

[citation needed] The route was proposed as one of the first four-lane highways in the U.S. to Pierre S. du Pont by John J. Raskob so as to run from Wilmington, Delaware, to the state capital, Dover.

Du Pont wanted a two-lane highway—the standard at the time, but Raskob suggested that with the growth and development of northern Delaware, there would be a future need for a four-lane one.