The Matanuska-Susitna Borough (Mat-Su) is a borough in southcentral Alaska, incorporated on 1 January 1964, with its seat at Palmer. It had 107,081 residents at the 2020 census and is described as the fastest-growing subdivision in Alaska.[1]
| Seat | Palmer |
|---|---|
| Largest incorporated community | Wasilla |
| Incorporated | 1 Jan 1964 |
| Population | 107,081 (2020) |
| Area | 25,258 sq mi |
| Growth 2010–2020 | 20.3% |
Geography
The borough takes its name from the Matanuska and Susitna rivers, which it fully contains and which empty into Cook Inlet on its southern border. It covers 25,258 square miles, of which 24,608 are land and 650 water. It borders Denali Borough to the north, the Copper River Census Area to the east, the Chugach Census Area, Anchorage and the Kenai Peninsula Borough to the south, and the Bethel and Yukon–Koyukuk Census Areas to the west.[1]
Protected lands
Parts of Chugach National Forest, Denali National Park and Preserve, the Denali Wilderness, and Lake Clark National Park and Preserve and its wilderness lie within the borough.[1]
Population growth
The population was 5,188 in 1960, 6,509 in 1970, 17,816 in 1980, 39,683 in 1990, 59,322 in 2000, 88,995 in 2010 and 107,081 in 2020, with a 2025 estimate of 118,666. The 2020 median age was 36.3, and about half of residents lived in rural areas.[1]
Communities
Wasilla is the largest incorporated community and Knik-Fairview the largest census-designated place. Others include Big Lake, Talkeetna, Willow, Trapper Creek, Sutton-Alpine, Chickaloon, Lake Louise, Skwentna, Petersville and Point MacKenzie. The borough is part of the Anchorage Metropolitan Statistical Area.[1]
Agriculture and government
The article describes the borough as one of the few agricultural areas in Alaska. It has a strong-manager form of government and one school district.[1]
FAQs
What is the borough seat? Palmer.
What is the largest city? Wasilla.
How fast is it growing? Population rose 20.3 percent from 2010 to 2020.
Which rivers is it named for? The Matanuska and Susitna rivers.
Sources
Key facts
- 107,081 residents
- Grew 20.3% in a decade
- 25,258 sq mi
Quick checkSeat?Show answer
Palmer.
Sources
- Wikipedia. Matanuska-Susitna Borough, Alaska. 2026 (accessed 2026-11-12)
Editorially reviewed by Specialty Digest Editorial TeamLast reviewed November 12, 2026Researched and drafted with AI assistanceReport an issue