Overview
Interstate 81 (I-81) is a north–south 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; Hagerstown in Maryland; Harrisburg and the Wyoming Valley in Pennsylvania; and Binghamton and Syracuse in New York.