Vermont Route 18 begins at the New Hampshire state line between Littleton and Waterford. After crossing the Connecticut River into Vermont, VT 18 veers westward to cross under I-93 into Lower Waterford village. VT 18 then continues northwest running closely parallel to I-93 on its west side for roughly  until Stiles Pond.
Vermont Route 18 starts at the New Hampshire-Vermont border, between Littleton and Waterford. Upon entering Vermont via the Connecticut River, VT 18 shifts westward to cross beneath I-93 in Lower Waterford village. The route then continues northwest, closely following I-93 on its western edge until Stiles Pond.