The Matanuska River is a river, approximately 75 miles (120 km) long, in Southcentral Alaska, United States. It drains a broad valley south of the Alaska Range known as the Matanuska-Susitna Valley.

Its headwaters are at Matanuska Glacier in the northern Chugach Mountains, approximately 100 miles (160 km) northeast of Anchorage. It flows generally west-southwest through the Mat-Su Valley, between the Chugach range to the south and the Talkeetna Mountains to the north. It flows past Palmer and enters the Knik Arm of Cook Inlet from the northeast approximately 25 mi (40 km) northeast of Anchorage.

The Mat-Su Valley is one of the most settled regions of Alaska and one of the few areas in the state to support agriculture. The river is a popular destination for whitewater rafting.

See also

• List of Alaska rivers

Rivers of Alaska