Matanuska-Susitna Valley (known locally as the Mat-Su or The Valley) is an area in Southcentral Alaska. It is south of the Alaska Range about 25 miles (40 km) from Anchorage, Alaska. It includes the valleys of the Matanuska River, the Knik River, and the Susitna River. The Matanuska Valley has become a suburban community for many people who work in Anchorage. It is now one of the most crowded areas in Alaska and includes the towns of Palmer, Wasilla, Big Lake, Houston, Willow and Talkeetna.

There are three mountain ranges in the area. They are the Alaska Range, the Talkeetna Mountains and the Chugach Mountains. There are both working and old gold mines in the mountains. Like many parts of Alaska, the Matanuska-Susitna Valley was carved by glaciers which left many lakes. Both the Matanuska and Susitna Rivers have lots of salmon.

The local government is called the Matanuska-Susitna Borough. Most of the United States is divided into counties, while Alaska is divided into boroughs and census areas. A few hundred Alaska Natives were joined by small numbers of Alaska sourdoughs between 1900 and 1930 when hundreds of American settlers were moved there by the United States Federal Government in the early 1930s.

The three rivers in the area have large amounts of glacial silt that is good for farming. The valley is one of the few areas in Alaska which supports large scale agriculture.

• Alaska Census data Archived 2011-06-07 at the Wayback Machine
• Matanuska-Susitna Borough website

61°23′N 150°15′W / 61.383°N 150.250°W / 61.383; -150.250