In Erving, Route 63 passes under Route 2 (the Mohawk Trail) without direct access between the two. Signage on both roads directs traffic along Prospect Street (signed as To 2 East and To 63 South) and along Forest Street (signed as To 2 East and To 63 North). Route 63 then heads north into Northfield, passing Northfield Mountain. It joins Route 10 (just east of Bennett's Meadow Bridge over the Connecticut River) for just under , before splitting just south of the New Hampshire state line. It shortly turns northwestward before entering the town of Hinsdale and becoming New Hampshire Route 63.