U.S. Route 340

U.S. Route 340
State	MD-PA-VA
Type	US
Route	340
Length mi	155
Established	1926
Direction a	South
Terminus a	Charles Town
Direction b	North
Terminus b	Frederick
Counties	Jefferson County, West Virginia; Loudoun County, Virginia; Clarke County, Virginia; Frederick County, Maryland

U.S. Route 340

U.S. Route 340 is a north–south United States Numbered Highway that connects communities across the Mid-Atlantic states of West Virginia, Virginia, and Maryland. The route links historic towns, national parks, and transportation corridors between Charles Town and Frederick, traversing the Shenandoah Valley and crossing the Potomac River. Established in the 1920s as part of the original U.S. Highway system, it serves regional traffic, military access, and tourism to sites such as Harper's Ferry National Historical Park, Shenandoah National Park, and the National Mall-adjacent corridors via connecting routes.

Route description

U.S. Route 340 begins in Charles Town where it intersects state routes and provides connections to Interstate 81 via feeder roads, then proceeds northeast toward Harper's Ferry and the confluence of the Potomac River and Shenandoah River. The highway crosses the Potomac on the Harry Flood Byrd Bridge adjacent to Harpers Ferry National Historical Park and enters Loudoun County near historic sites such as Bluemont and Aldie, linking to U.S. Route 15 and the commuter networks feeding Washington, D.C.. Continuing north it parallels the western slopes of the Blue Ridge Mountains and the Shenandoah River, passing close to Bentonville Battlefield and providing access to Shenandoah Valley battlefields.

In Clarke County US 340 runs near Berryville and through agricultural landscapes before entering Frederick County, where it connects with Interstate 70 and terminates near Frederick. Along its length it intersects multiple U.S. routes and state highways including U.S. Route 11 near Winchester and U.S. Route 50 via arterial links, serving as a corridor for commuters, freight, and tourists heading to Antietam National Battlefield and Gettysburg National Military Park via adjacent highways.

History

US 340 was designated in the original 1926 U.S. Highway plan to link the Blue Ridge Mountains corridor with the industrial and agricultural communities of the Mid-Atlantic. Early 20th-century improvements were influenced by organizations such as the American Association of State Highway Officials and state departments like the Virginia Department of Transportation and the Maryland State Highway Administration, reflecting broader trends in the Good Roads Movement and interwar highway expansion. The route’s alignment has been altered periodically to accommodate bypasses around Charles Town and to adapt river crossings affected by floodplain management and projects by the U.S. Army Corps of Engineers.

During World War II and the Cold War, US 340’s role in connecting military installations and logistics hubs—via links to Fort Detrick and airfields used by the United States Air Force—led to capacity upgrades and bridge reinforcements. In the late 20th and early 21st centuries, community-led preservation efforts involving groups such as the National Trust for Historic Preservation and local historical societies shaped decisions about scenic overlays and access to sites like Harpers Ferry and the Shenandoah National Park corridor.

Major intersections

Along its course US 340 intersects several major routes and facilities: - In Charles Town: intersections with state routes feeding Interstate 66 and Interstate 81 corridors. - Near Harper's Ferry: crossing of the Potomac River with access to U.S. Route 522 and connections toward Martinsburg. - In Loudoun County: junctions with U.S. Route 15 and state routes linking to Leesburg and Dulles International Airport. - Near Berryville and Winchester: connections to U.S. Route 11 and corridors toward Interstate 81. - At its northern terminus in Frederick: interchange with Interstate 70 and links to U.S. Route 40 and regional arteries to Baltimore and Washington, D.C..

Auxiliary routes

Several auxiliary and connector routes have been designated to serve bypasses, spurs, and business loops associated with US 340, including state-maintained business routes through Charles Town and Berryville. These include connections to Maryland Route 180 near Frederick and feeder roads to Interstate 270 commuter corridors. Local agencies such as the Virginia Department of Transportation have implemented truck routes and scenic byway designations to divert heavy vehicles from historic districts like Harpers Ferry and Shenandoah National Park access points.

Traffic and maintenance

Traffic volumes on US 340 vary from rural two-lane segments in Clarke County to multi-lane arterial sections near Frederick and commuter-heavy corridors in Loudoun County. Maintenance responsibilities are shared among the West Virginia Division of Highways, the Virginia Department of Transportation, and the Maryland State Highway Administration, with periodic resurfacing, bridge inspections, and safety upgrades funded through state transportation budgets and federal programs administered by the Federal Highway Administration. Congestion management programs coordinate with regional planning bodies like the Metropolitan Washington Council of Governments to address peak commuter flows toward Washington, D.C..

Cultural and economic impact

US 340 supports tourism to heritage sites such as Harpers Ferry, Antietam National Battlefield, and access corridors to Shenandoah National Park, bolstering local economies dependent on outdoor recreation and heritage tourism. The route also underpins agricultural markets in the Shenandoah Valley and provides freight access for manufacturing and logistics firms in Frederick County and Loudoun County, connecting to interstates that serve ports like Port of Baltimore and regional airports such as Dulles International Airport. Preservation groups and chambers of commerce in towns along the highway collaborate with state agencies and national organizations like the National Park Service to balance economic development with conservation of historic landscapes.

Category:United States Numbered Highways Category:Roads in Maryland Category:Roads in Virginia Category:Roads in West Virginia