sentences:  I-81 is the primary north–south Interstate highway in Washington County, connecting Hagerstown with Chambersburg and Harrisburg to the north and Martinsburg, Winchester, and Roanoke to the south.The idea of a north–south bypass of Hagerstown to relieve congestion on the contemporary main highway through the Hagerstown Valley, U.S. Route 11 (US 11), predates the Interstate system.Construction on the Hagerstown Bypass began in the mid-1950s and was completed in 1958 from US 40 north to the Pennsylvania state line.