 Route 66 continues through Westhampton along Main Road, which crosses the upper reaches of the Manhan River and descends to that river's North Branch at the village of Loudville at the Northampton city line.The highway continues into the city as Westhampton Road, but that name changes to Rocky Hill Road at Florence Road then Chapel Street and Prince Street before its final name of West Street.Route 66's West Street section passes by the site of the former Northampton State Hospital, crosses the Mill River, and passes through the campus of Smith College.