Input (grade 13): The interstate's southern end is in New Haven, Connecticut at Interstate 95; its northern end is at Derby Line, Vermont, a village in the town of Derby, at the Canadian border, where it continues as Autoroute 55.
Output (grade 7): Its south end is at New Haven, Connecticut, and its north end is at Derby Line, Vermont; near the Canadian border. The interstate follows the Connecticut River for much of its length.