New Hampshire State Route 18 is a north-south highway in Northern Grafton County. It runs from Interstate 93/U.S. Rt. 3, near Franconia, to the Vermont/New Hampshire State Line, near Waterford. NH St Rt 18 passes through the following towns in Grafton County. Franconia Bethlehem Littleton NH St Rt 18 is mutli-plexed in Grafton County. New Hampshire State Route 116, from Franconia to Littleton. U.S. Rt. 302, from Bethlehem to Littleton.