County Maps US

Martin County, Minnesota

A county in Minnesota, ranked 49 of 87 by population.

CountyFIPS 27091

Within Minnesota
Martin County, highlighted, with the areas around it. Boundaries generalised from the 2025 Census cartographic boundary file; neighbour fills carry no data. The dot marks Fairmont, the county seat, located via the 2025 Census Gazetteer.

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Population
19,440
-558 (-2.8%) since 2020
Land area
712.3
square miles. A further 2.4% of the total area is water
Population density
27.3
people per square mile, computed rather than published
County seat
Fairmont
Seat of county government.
Established
1857
168 years ago
Largest city
Fairmont city
Population 10,099.

Sources: US Census Bureau, Population Estimates Program, Vintage 2025 Population Estimates, released 26 March 2026; US Census Bureau, Gazetteer Files, 2025 Gazetteer Files, released 10 September 2025; Wikidata (CC0), Wikidata. Retrieved 30 August 2026.

Satellite view

Aerial imagery of Martin County with its boundary drawn on top. A map shows you the shape; this shows you what is inside it, and which side of the line a place falls on.

Aerial view of Martin County, Minnesota from the USGS National Map, with its boundary outlined
Imagery: USGS National Map, USGS Imagery Only, public domain, requested from USGS by your browser when you reach this point on the page, at 800 by 652 pixels. The boundary is the 2025 Census cartographic boundary file, reprojected to Web Mercator to match the imagery. You can also open the USGS National Map viewer.

Where Martin County ranks

Position among the 87 counties of Minnesota, and among all 3,144 US counties and county-equivalents. Computed from the figures on this page.

MeasureValueIn MinnesotaNationally
Population19,44049th of 871,862nd of 3,144
Land area712.3 sq mi39th of 871,286th of 3,144
Population density27.3 per sq mi44th of 872,007th of 3,144
Median household income$59,50786th of 872,123rd of 3,143

Full data for Martin County

Every figure below is attributed to the Census Bureau product it came from, with the vintage of that product.
MeasureValueSource and vintage
Population19,440Vintage 2025 Population Estimates
Population in 202019,998Vintage 2025 Population Estimates
2020 estimates base?20,038Vintage 2025 Population Estimates
Land area712.3 sq mi2025 Gazetteer Files
Water area17.2 sq mi2025 Gazetteer Files
Total area729.6 sq mi2025 Gazetteer Files
Population density?27.3 per sq miComputed: Vintage 2025 estimates divided by 2025 Gazetteer land area
Median household income$59,507American Community Survey 2020-2024 5-Year Estimates
Median home value$163,500American Community Survey 2020-2024 5-Year Estimates
Median age43.9American Community Survey 2020-2024 5-Year Estimates
Households8,839American Community Survey 2020-2024 5-Year Estimates
Housing units9,729American Community Survey 2020-2024 5-Year Estimates

Sources: US Census Bureau, Population Estimates Program, Vintage 2025 Population Estimates, released 26 March 2026; US Census Bureau, Gazetteer Files, 2025 Gazetteer Files, released 10 September 2025; US Census Bureau, American Community Survey, American Community Survey 2020-2024 5-Year Estimates, released 29 January 2026. Population density is computed here, not published: it divides the Vintage 2025 population estimate by the 2025 Gazetteer land area, which are two different Census products. Retrieved 30 August 2026.

How the population changed

The Census Bureau publishes the components behind an estimate, not just the total. For the year to July 2025:

Births minus deaths
-75
199 births, 274 deaths
Net migration
-48
More people moved out than moved in.

Source: US Census Bureau, Population Estimates Program, Vintage 2025 Population Estimates, released 26 March 2026. Retrieved 30 August 2026.

The 6 areas bordering Martin County

Ordered by the length of the border actually shared, which the Census Bureau publishes in its county adjacency file and which no other county reference presents.

Bordering areaStateShared borderPopulation
Watonwan CountyMinnesota24 mi11,459
Faribault CountyMinnesota24 mi13,888
Jackson CountyMinnesota24 mi9,857
Emmet CountyIowa21 mi9,107
Kossuth CountyIowa9.8 mi14,322
Blue Earth CountyMinnesota6.1 mi70,634

Source: US Census Bureau, County Adjacency File, 2025 County Adjacency File, released 15 September 2025. Retrieved 30 August 2026.

All 87 counties of Minnesota

Open the interactive Minnesota county map, or jump straight to any of them.

Data on this page last rebuilt 30 August 2026. How these figures are produced.