High Quality Content by WIKIPEDIA articles! Pennsylvania Route 51 (PA 51) is a major state highway in Western Pennsylvania. It runs for 89 miles (143 km) from Uniontown to the Ohio state line near Darlington, where it connects with Ohio State Route 14. Route 51 is the termination point for Pennsylvania Route 43, Pennsylvania Route 48 and Pennsylvania Route 88. Century III Mall is located on this road in West Mifflin. The Route is a major connection from Uniontown and the rest of Fayette County to Pittsburgh.