 I-91 travels along the eastern border of Vermont and serves as a major transportation corridor for eastern Vermont and western New Hampshire.Many exits along Vermont's length of I-91 feature New Hampshire towns on the guide signs (for example, exit 3, which lists Brattleboro and Keene, as the points of access).The length of I-91 within Vermont is and has two lanes in each direction the entire way from the Massachusetts state line at Guilford to Derby Line at the Canadian border (nearly two-thirds of I-91's length) with 29 Vermont interchanges.