After crossing the Musconetcong River, CR 519 enters Pohatcong Township, Warren County and immediately turns north at the CR 627 intersection into wooded areas with some farms and homes. The route winds to the northwest and passes under I-78. After this, CR 519 becomes Springtown Road and briefly forms the border between Alpha to the west and Pohatcong Township to the east before completely entering Alpha and continuing north. The road becomes Third Avenue and passes a few businesses before crossing under Norfolk Southern's Lehigh Line and passing several homes with some commercial establishments. After crossing back into Pohatcong Township and becoming Hawk Avenue, CR 519 intersects Route 122 and turns northwest to form a concurrency with that route on New Brunswick Avenue. CR 519 splits from Route 122 by turning northeast onto Saint James Avenue and passing more homes. The road passes near commercial development as it comes to a junction with US 22. Past US 22, the route becomes Uniontown Road and enters Greenwich Township. It passes near a mix of farm fields and residential neighborhoods as it makes a curve to the north and crosses into Lopatcong Township. CR 519 briefly becomes a divided highway as it passes under Norfolk Southern's Washington Secondary before crossing Route 57.