Rapid River is a 6.0-mile-long (9.7 km)[1] river in the northwestern portion of the US state of Maine flowing from Lower Richardson Lake to Umbagog Lake.

Despite its short length, it forms the end of a major portion of the Umbagog Lake and Androscoggin River watersheds.

True to its name, Rapid River contains class III–IV rapids for most of its length, including some good spots for playboating and riverboarding.

Locals omit the word "the" when referring to the river.

This article related to a river in Maine is a stub.