Though labeled as east–west, the road has a north–south alignment for half of its length.

The eastern terminus of NH 77 is in Dunbarton at New Hampshire Route 13.

NH 77's western terminus is at NH 13 in New Boston, just north of the town's central village, where it forks off to the north on Weare Road.

Heading due north and passing by the eastern slopes of Mount Wallingford, the two routes cross through the main village of Weare at the center of town, where the road becomes North Stark Highway.

and upon crossing the Piscataquog River, at a hard right turn NH 77 leaves NH 114/Stark Highway to join Concord Stage Road.