Nearly the entire length of the North Branch is in the town of Milan, New Hampshire.

The river briefly enters the city of Berlin, where it passes through Head Pond, then heads north back into Milan, running parallel to the Upper Ammonoosuc until the two rivers join in the village of West Milan.

The Androscoggin River, just three miles to the east, flows parallel to the two Upper Ammonoosuc branches, but in the opposite direction.

The St. Lawrence and Atlantic Railroad follows the North Branch from Head Pond to West Milan.

This article related to a river in New Hampshire is a stub.