Interstate 91 (I-91) is an Interstate Highway in the New England region of the United States. It provides the primary north–south thoroughfare in the western part of the region. The Interstate generally follows the course of the Connecticut River. Its southern terminus is in New Haven, Connecticut, at Interstate 95. The northern terminus is in the village of Derby Line, Vermont, at the Canadian border. Past the Derby Line–Rock Island Border Crossing, the road continues as Quebec Autoroute 55. I-91 is the longest of three Interstate highways whose entire route is located within the New England states (the other two highways being I-89 and I-93) and is also the only primary (two-digit) Interstate Highway in New England to intersect all five of the other highways that run through the region. From Wikipedia.