 It passes the Uniontown Hospital before ending at US Route 40 Business (Main St.).In 1911, what would become PA 21 was designated as part of Legislative Route 256 between the West Virginia border and Rogersville, Legislative Route 111 between Rogersville and Waynesburg, and Legislative Route 112 between Waynesburg and Uniontown.PA 21 was designated in 1927 to run from the West Virginia border east to US 40 in Uniontown.