Martin County area

Population and density of Martin County

The Census Bureau estimates that 19,440 people lived in Martin County on July 1, 2025. That ranks #1,921 of 3,222 county equivalents nationally and #49 of 87 in Minnesota. Since the April 1, 2020 estimates base of 20,038, the population has declined by 598 (−3%), compared with +2.2% for Minnesota as a whole.

With 712.3 square miles of land, that is 27 people per square mile (11 per km²), placing Martin County #2,086 nationally for density and #44 in Minnesota. The median county equivalent has 47 people per square mile; the Minnesota median is 27. Put another way, there are about 23 acres of land per resident.

U.S. Census Bureau, Vintage 2025 population estimates. Estimates are revised each year and are not decennial census counts. Density divides the whole population by the whole county’s land area, so it describes an average, not how settlement is distributed within the county. Population sources and methods.

Cities and towns in Martin County

Martin County is divided into 30 municipalities and townships. In Minnesota, county subdivisions are local governments, and together they cover all of the county’s land and residents.

The most populous is Fairmont city, with 10,099 residents (51.9% of the county). The largest by land is Waverly township, at 36.7 mi², or 5.2% of the county’s land.

Population: U.S. Census Bureau Vintage 2025 subcounty estimates, counting only the part of each subdivision inside Martin County. Land: 2026 Census Gazetteer. How communities are listed.

Metropolitan area

Martin County is a central county of the Fairmont, MN Micropolitan Statistical Area. Martin County is the area’s only county equivalent, so the micro area has the same 712.3 square miles of land. By combined land it ranks #301 of 542 micropolitan areas, and #523 by population.

ZIP codes

15 ZIP Code Tabulation Areas have land in Martin County; 11 of them have most of their land inside the county, and the others mainly cover neighboring areas.

560135602756031560395607556088560985611156121561275616056162561715617656181

ZIP Code Tabulation Areas are the Census Bureau’s approximations of USPS ZIP Code service areas, from the 2020 Census relationship files. Lighter codes have less than half of their land in this county. Post-office-box and single-address ZIP Codes have no tabulation area.

Counties bordering Martin County

Martin County shares a land border with 6 county equivalents, including 2 in Iowa. It has more land than 3 of them. The largest neighbor is Kossuth County (972.7 mi²) and the smallest is Emmet County (395.9 mi²). Together with its neighbors, Martin County forms a block of 4,679.2 mi² of land, of which it holds 15.2%.

How big is Martin County compared with U.S. states?

Martin County has less land than any of the 50 states. Rhode Island, the smallest state by land area, has 1,033.9 mi², about 1.5 times as much. Minnesota’s county land could hold about 112 areas the size of Martin County.

Another way to picture it: the same land area would fill a square about 26.7 miles (43 km) on each side. Real county shapes are rarely square, so this is a scale reference rather than a width or driving distance.

State figures are the sums of each state’s county-equivalent land measurements in the same Census release, so states and counties are compared on the same basis. Published state totals can differ slightly because of rounding. Compare all states · Counties bigger than entire states.

What stands out about Martin County?

Martin County has more land than 1,936 of the other 3,221 county equivalents in the dataset.

A median is the middle county-equivalent measurement, not the average of the largest and smallest. All three bars use the same linear scale. Very small areas may appear as a thin sliver; the labels retain their values.

Does including water change its rank?

Using land plus water places Martin County at #1,324 nationally by total area, 38 places farther from the top than its land rank. Other county equivalents gain more area when their water measurements are included.

Its water share is 2.4%, compared with a national county-equivalent median of 1.2% — 1.2 percentage points higher. This describes the statistical geography’s land/water mix, not flood exposure or developable land.

Closest positions in the national land ranking

These entries sit immediately beside Martin County in the national ranking. They can be in different states and are not necessarily geographic neighbors.

Calculated from the same Census release as the area table. Total-area order uses original ALAND + AWATER; water shares and chart labels use published square miles. Calculation details.