 Just after crossing the Westmoreland County/Somerset County line (the dividing line between the Pittsburgh metropolitan area and the Johnstown, Pennsylvania metro area, PA 31 provides entrance to the Hidden Valley Ski Resort area.After winding past rural Westmoreland and Fayette Counties, PA 31 enters Somerset County and encounters the borough of Somerset.Immediately after entering Somerset, PA 31 intersects Pennsylvania Route 281 and forms a concurrency on one-way pairs.