Some older signs in downtown Somersworth show NH 236 as a north–south highway, but more recent signage is indicative of its east–west orientation.

Upon reaching downtown, the highway turns to the north and intersects NH 9 (High Street).

NH 236 ends, but its implied continuation, Maine State Route 236, begins less than 1⁄4 mile (0.40 km) past the state line, splitting from SR 9 in the town center of Berwick.

NH 236 runs through the western side of Somersworth, and is known as West High Street.

The section cosigned with NH 9 downtown runs along High and Market Streets.