 The northern terminus is at PA 64 in Zion.The road is known as Pennington Road, Halfmoon Valley Road, Centre Line Road, Buffalo Run Road, Water Street, High Street, Bishop Street, and Zion Road.PA 550 begins at an intersection with PA 453 and PA 45 Truck in Snyder Township, Blair County, heading northeast on a two-lane undivided road concurrent with PA 45 Truck.