Matanuska-Susitna Borough, Alaska

Matanuska-Susitna Borough
Location within the U.S. state of Alaska
Alaska's location within the U.S.
Coordinates: 62°24′N 149°35′W / 62.4°N 149.58°W / 62.4; -149.58
Country United States
State Alaska
IncorporatedJanuary 1, 1964
Named afterMatanuska River and Susitna River
SeatPalmer
Largest CDPKnik-Fairview
Government
  Borough MayorEdna DeVries
Area
  Total
25,258 sq mi (65,420 km2)
  Land24,608 sq mi (63,730 km2)
  Water650 sq mi (1,700 km2)  2.6%
Population
 (2020)
  Total
107,081
  Estimate 
(2024)
117,613
  Density4.2/sq mi (1.6/km2)
Time zoneUTC−9 (Alaska)
  Summer (DST)UTC−8 (ADT)
Congressional districtAt-large
Websitewww.matsugov.us

Matanuska-Susitna Borough (often referred to as the Mat-Su Borough) is a borough located in the U.S. state of Alaska. Its borough seat is Palmer, and the largest community is the census-designated place of Knik-Fairview. As of the 2020 census, the borough's population was 107,081.

The borough is part of the Anchorage Metropolitan Statistical Area, along with the municipality of Anchorage on its south.

The Mat-Su Borough is so designated because it contains the entire Matanuska and Susitna Rivers. They empty into Cook Inlet, which is the southern border of the Mat-Su Borough. It is one of the few agricultural areas of Alaska.