Pennsylvania Route 412 (PA 412) is a 17.75-mile (28.57 km) long north–south state route located in Northampton and Bucks counties in southeastern Pennsylvania. Its southern terminus is at Pennsylvania Route 611 in the Nockamixon Township community of Harrow. Its northern terminus is at Pennsylvania Route 378 (Wyandotte Street) in Bethlehem.

In the Springtown, Springfield Township area, PA 412 runs concurrent with PA Route 212 for about two miles (3 km). The two routes split south of Springtown. By following PA 212 west, travelers can reach Quakertown, where the route intersects with PA Route 313. Alternatively, PA 212 east leads to Riegelsville, where it intersects with PA Route 611.

Route 412 begins at an intersection with PA Route 611 in the hamlet of Harrow, a part of Nockamixon Township. The route traverses Nockamixon Township as Durham Road with a northwest and southeast alignment. About 2,795 feet north to the southern terminus, Route 412 intersects PA Route 563. After crossing PA 563, Route 412 continues northward, passing the rural land of Bucks County. In the township of Springfield, Route 412 runs concurrent with PA Route 212 for 1.9 miles (3.1 km). The direction of the concurrency is east and west. At milepost 8.84, Route 412 splits from PA 212 and travels to the north.

Route 412 enters Northampton County from the south as Leithsville Road. Upon entering the borough of Hellertown, Route 412 is named Main Street, the principal north and south street of Hellertown. Route 412 interchanges exit 67 of Interstate 78, at the boundary of Hellertown and the city of Bethlehem. Outside of Hellertown, Route 412 is called Hellertown Road, passing the southeastern sections of Historic Bethlehem. Route 412 crosses the Saucon Creek at the junction with Shimersville Road, while turning to the west. This section is now East 4th Street.

The route runs directly through what is still left of this former steel manufacturer — Bethlehem Steel. It also is the main access route to the new Sands Casino Resort Bethlehem. The route turns to the northwest and is named Daly Avenue, then intersects Stefko Boulevard; a crossing of the Lehigh River via the Minsi Trail Bridge. West of Stefko Blvd., Route 412 intersects and becomes East Third Street. At this time, Route 412 also passes the Artsquest Center, a new art and music venue in Bethlehem. After becoming 3rd Street, the route intersects New Street; another crossing of the Lehigh River via the Fahy Bridge. Briefly west of New Street, Route 412 turns southward to become Broadhead Avenue and turns again to the southwest to become Broadway. Upon becoming Broadway, the route terminates at an intersection with PA Route 378 at an intersection known locally as Five Points.

Signed in 1928 as a spur route of PA 12, which ran on the current PA 378 alignment.