U.S. Route 13 Business (US 13 Bus.) is an 8.19-mile (13.18 km) business route of US 13 that runs through the heart of Wilmington in New Castle County, Delaware, where US 13 bypasses downtown Wilmington to the east, running near Interstate 495 (I-495) and the Delaware River. US 13 Bus. begins at US 13 at the southern border of Wilmington and heads north toward the downtown area, where it splits into a one-way pair. Past downtown, the business route heads through the northeastern part of the city on North Market Street before continuing through suburban Brandywine Hundred on Philadelphia Pike. US 13 Bus. reaches its northern terminus at US 13 in Claymont. US 13 Bus. is a four-lane road for much of its length.