The Swift River is a 26.7 miles (43 km) river in western 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...

. It is a tributary of the 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...

, which flows to the Kennebec River

Kennebec River

The Kennebec River is a river that is entirely within the U.S. state of Maine. It rises in Moosehead Lake in west-central Maine. The East and West Outlets join at Indian Pond and the river then flows southward...

 near its mouth at the Atlantic Ocean

Atlantic Ocean

The Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about , it covers approximately 20% of the Earth's surface and about 26% of its water surface area...

.

The Swift River rises in Franklin County

Franklin County, Maine

Franklin County is a county located in the U.S. state of Maine. As of 2010, the population was 30,768. Its county seat is Farmington.Franklin County was established on 9 May 1838.-Geography:...

 at the outlet of Swift River Pond, a small water body southeast of the 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...

s. The river flows south into Oxford County

Oxford County, Maine

Oxford County is a county located in the U.S. state of Maine with a population of 57,833 as of the 2010 U.S. census. Its county seat is Paris.Part of Oxford County is included in the Lewiston-Auburn, Maine, metropolitan New England City and Town Area while a different part of Oxford County is...

 through the towns of Byron

Byron, Maine

Byron is a town in Oxford County, Maine, United States. The population was 121 at the 2000 census. Home to Coos Canyon on the Swift River, Byron includes the village of Houghton.-History:...

, Roxbury

Roxbury, Maine

Roxbury is a town in Oxford County, Maine, United States. The population was 384 at the 2000 census. Ellis Pond is popular with recreational fishermen.-History:...

, and Mexico, ending at the Androscoggin River at the town boundary between Mexico and Rumford, and flowing through the downtown of the combined urban area formed by the two towns.