New Hampshire Route 85 (abbreviated NH Route 85 or NH 85) is a 4.854-mile-long (7.812 km) north–south state highway in Rockingham County in southeastern New Hampshire.

The northern terminus is in Newfields at New Hampshire Route 108.

It runs along the west side of the Squamscott River for its entire length, opposite to NH 108, which runs east of the river.

Heading westbound on Water Street, which initially carries NH 27 and NH 111A, these two routes transition over to Main Street, while Water Street splits off due north to carry NH 85.

The road turns northeast for its last mile and ends at an intersection with NH 108, which provides access to the closely neighboring towns of Newmarket and Stratham.