Interstate 81

Interstate 81
I-81 highlighted in red
Route information
Length	855.02 mi[1] (1,376.02 km)
Existed	1957–present
NHS	Entire route
Major junctions
South end	I-40 in Dandridge, TN
Major intersections	I-26 / US 23 near Kingsport, TN I-77 from Wytheville, VA to Fort Chiswell, VA I-64 from Lexington, VA to Staunton, VA I-70 at Hagerstown, MD US 11 to I-76 Toll / Penna Turnpike in Carlisle, PA I-83 / US 322 / US 22 in Harrisburg, PA I-78 at Union Township, PA I-80 at Drums, PA I-84 / I-380 / US 6 in Dunmore, PA I-90 Toll / New York Thruway near Syracuse, NY
North end	Highway 137 on Thousand Islands Bridge at Wellesley Island, NY/Hill Island, ON
Location
Country	United States
States	Tennessee, Virginia, West Virginia, Maryland, Pennsylvania, New York
Highway system
Interstate Highway System Main Auxiliary Suffixed Business Future

Interstate 81 (I-81) is a north–south (physically northeast–southwest) Interstate Highway in the eastern part of the United States. Its southern terminus is at I-40 in Dandridge, Tennessee; its northern terminus is on Wellesley Island, New York at the Canadian border, where the Thousand Islands Bridge connects it to Highway 137 and ultimately to Highway 401, the main Ontario freeway connecting Detroit via Toronto to Montreal. The major metropolitan areas along the route of I-81 include the Tri-Cities of Tennessee; Roanoke in Virginia; Harrisburg and the Wyoming Valley in Pennsylvania; and Syracuse in New York.

I-81 largely traces the paths created down the length of the Appalachian Mountains through the Great Appalachian Valley by migrating animals, indigenous peoples, and early settlers. It also follows a major corridor for troop movements during the Civil War.^[2] These trails and roadways gradually evolved into US Route 11 (US 11); I-81 parallels much of the older US 11.^[3] Being mostly rural in nature, I-81 is heavily used as a trucking corridor and is often used as a bypass of busier and more congested Interstates to the east such as I-95; for this reason, it is also used heavily by drug and human traffickers, as it is less monitored by law enforcement than I-95. This led to the Federal Bureau of Investigation (FBI) forming a taskforce to combat the issue in 2017.^[4][5]

The I-81 Corridor Coalition, a six-state coalition, was organized to handle issues along I-81, such as truck traffic and air pollution; the commission meets annually.^[6] I-81 is part of the fastest route between the capital of the US (Washington, D.C.) and the capital of Canada (Ottawa) and Mexico (Mexico City).^[7][8]