The Rapid River is a 6 miles (9.7 km) river in the northwestern portion of the US state of Maine

Maine

Maine is a state in the New England region of the northeastern United States, bordered by the Atlantic Ocean to the east and south, New Hampshire to the west, and the Canadian provinces of Quebec to the northwest and New Brunswick to the northeast. Maine is both the northernmost and easternmost...

 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

Androscoggin River

The Androscoggin River is a river in the U.S. states of Maine and New Hampshire, in northern New England. It is long and joins the Kennebec River at Merrymeeting Bay in Maine before its water empties into the Gulf of Maine on the Atlantic Ocean. Its drainage basin is in area...

 watersheds. Much of this watershed is covered by (from downstream to upstream) Lower and Upper Richardson Lakes, Mooselookmeguntic Lake

Mooselookmeguntic Lake

Mooselookmeguntic Lake is located in Franklin County and Oxford County, Maine, in the United States. It is part of the Androscoggin River watershed....

, Cupsuptic Lake and Rangeley Lake

Rangeley Lake

Rangeley Lake is located in Franklin County, Maine in the United States. It is fed by several streams. Its waters flow out from the lake's northwestern end into the short Rangeley River, then into Mooselookmeguntic Lake, and ultimately into the Androscoggin River, Merrymeeting Bay, the lower...

. The major tributaries of this system are the Cupsuptic

Cupsuptic River

The Cupsuptic River is a river in Maine. It flows from its source near the Canada – United States border to Cupsuptic Lake, the northern arm of Mooselookmeguntic Lake, which drains via other lakes into the Androscoggin River...

, Kennebago

Kennebago River

The Kennebago River is a river in northwestern Maine. It is a tributary of Cupsuptic Lake, an arm of Mooselookmeguntic Lake. Via a chain of lakes and the Rapid River, it is part of the Androscoggin River watershed.-References:**...

 and Rangeley

Rangeley River

The Rangeley River is located in Franklin County, Maine, in the United States. It is only about a mile long, connecting the outlet of Rangeley Lake with Mooselookmeguntic Lake.It is part of the Androscoggin River watershed....

 rivers, all of which flow into Cupsuptic Lake.

True to its name, the Rapid River contains class III–IV

International Scale of River Difficulty

The International Scale of River Difficulty is a standardized scale used to rate the safety of a stretch of river, or a single rapid. The grade reflects the technical difficulty and skill level required associated with the section of river...

 rapids for most of its length, including some good spots for playboating

Playboating

Playboating is a discipline of whitewater kayaking or canoeing where the paddler performs various technical moves in one place , as opposed to downriver whitewater canoeing or kayaking where the objective is to travel the length of a section of river...

 and riverboarding

Riverboarding

Riverboarding is a boardsport in which the participant lies prone on their board with fins on their feet for propulsion and steering. This sport is also known as hydrospeed in Europe and as riverboarding or white-water sledging in New Zealand, depending on the type of board used...

.