 PA 340 intersects US 30 near Lancaster, PA 772 in Intercourse, PA 897 in White Horse, PA 10 in Compass, PA 82 in Wagontown, and US 30 again near Thorndale.The route follows the route of the King's Highway that linked Lancaster and Philadelphia in colonial times and is, in fact, named King's Highway during the first few miles of its length near Thorndale.PA 340 was first designated in 1928 between US 222/PA 240 east of Lancaster and US 30/PA 1 in Gap, following its current route to White Horse before turning south to Gap.