Pennsylvania Route 3 is a 24.3-mile (39.1 km) state highway located in the southeastern portion of Pennsylvania. The route runs from U.S. Route 322 Business in West Chester east to PA 611 in Philadelphia.

U.S. Route 322 Business is a business route of US 322 in the borough and surrounding townships of West Chester in Chester County, Pennsylvania. US 322 bypasses West Chester to the north and east on the West Chester Bypass while US 322 Bus. heads through the downtown area. The business route begins at US 322 northwest of the borough and heads southeast, entering West Chester on Hannum Avenue. US 322 Bus. heads east into downtown West Chester along the one-way pair of West Market and West Chestnut streets. In the center of the borough, the route heads south along South High Street, passing through the West Chester University of Pennsylvania campus as it leaves the borough. US 322 Bus. comes to its eastern terminus at an interchange with US 202/US 322 at the southern terminus of the bypass.