Charlestown is served by New Hampshire Routes 11, 12 and 12A. Routes 11 and 12 lead north from the town center to downtown Claremont. Route 12 leads south to North Walpole, adjacent to Bellows Falls, Vermont, and to Keene, New Hampshire. Route 11 leads northwest from the center of Charlestown to the Cheshire Bridge (the old toll bridge) across the Connecticut River, after which it becomes Vermont Route 11 and provides access to Interstate 91 and U.S. Route 5 in Vermont.