County outline
Where Mahnomen County is located
Area breakdown
Land accounts for 95.7% of Mahnomen County’s measured area and water for 4.3%. Its combined area converts to 1,509.7 square kilometers or approximately 373,060 acres.
Green: land · blue: water
| Measurement | Square miles | Square kilometers | Acres |
|---|---|---|---|
| Land | 557.867 | 1,444.869 | 357,034.9 |
| Water | 25.039 | 64.851 | 16,025 |
| Total | 582.906 | 1,509.72 | 373,059.8 |
How Mahnomen County compares
By original Census land area, Mahnomen County ranks #59 of 87 in Minnesota and #1858 of 3,222 nationally. National rankings include the 50 states, District of Columbia, and Puerto Rico.
Its land area is 0.827 times the Minnesota county-equivalent median of 674.6 square miles. It accounts for 0.7% of the combined county land area in the state.
See the complete Minnesota ranking · What counts as a county equivalent?
Population and density of Mahnomen County
The Census Bureau estimates that 5,153 people lived in Mahnomen County on July 1, 2025. That ranks #2,886 of 3,222 county equivalents nationally and #82 of 87 in Minnesota. Since the April 1, 2020 estimates base of 5,402, the population has declined by 249 (−4.6%), compared with +2.2% for Minnesota as a whole.
With 557.9 square miles of land, that is 9.2 people per square mile (3.6 per km²), placing Mahnomen County #2,668 nationally for density and #73 in Minnesota. The median county equivalent has 47 people per square mile; the Minnesota median is 27. Put another way, there are about 69 acres of land per resident.
| July 1 | 2020 | 2021 | 2022 | 2023 | 2024 | 2025 |
|---|---|---|---|---|---|---|
| Estimate | 5,373 | 5,384 | 5,320 | 5,307 | 5,241 | 5,153 |
| Change | — | +11 | −64 | −13 | −66 | −88 |
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 Mahnomen County
Mahnomen County is divided into 19 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 Mahnomen city, with 1,181 residents (22.9% of the county). The largest by land is Marsh Creek township, at 37.7 mi², or 6.8% of the county’s land.
| County subdivision | Population 2025 | Since 2020 | Land mi² | Share of county land |
|---|---|---|---|---|
| Mahnomen cityCounty seat | 1,181 | −4.8% | 1.059 | 0.2% |
| Twin Lakes township | 724 | −4.5% | 32.8 | 5.9% |
| Pembina township | 630 | −4.8% | 36.3 | 6.5% |
| Waubun city | 389 | −5.1% | 0.514 | 0.1% |
| Island Lake township | 300 | −4.5% | 34.4 | 6.2% |
| Little Elbow township | 275 | −4.5% | 31.3 | 5.6% |
| Oakland township | 251 | −4.6% | 32.6 | 5.8% |
| Lake Grove township | 173 | −4.4% | 35.1 | 6.3% |
| La Garde township | 161 | −3.6% | 33.7 | 6% |
| Chief township | 152 | −4.4% | 34.8 | 6.2% |
| Marsh Creek township | 136 | −4.2% | 37.7 | 6.8% |
| Heier township | 130 | −5.8% | 33.7 | 6% |
| Clover township | 129 | −3% | 34.9 | 6.3% |
| Popple Grove township | 112 | −4.3% | 37.3 | 6.7% |
| Rosedale township | 111 | −4.3% | 35.1 | 6.3% |
Show the other 4 subdivisions
| Name | Population 2025 | Since 2020 | Land mi² |
|---|---|---|---|
| Beaulieu township | 95 | −4% | 33.7 |
| Bejou city | 81 | −4.7% | 0.287 |
| Bejou township | 67 | −4.3% | 37.4 |
| Gregory township | 56 | −5.1% | 35.2 |
Population: U.S. Census Bureau Vintage 2025 subcounty estimates, counting only the part of each subdivision inside Mahnomen County. Land: 2026 Census Gazetteer. How communities are listed.
Metropolitan area
Mahnomen County is not part of any metropolitan or micropolitan statistical area in the Office of Management and Budget’s July 2023 delineation; 1,306 other county equivalents are also outside one. These areas are built around an urban core of at least 10,000 people plus the counties tied to it by commuting, so counties outside them are generally rural.
ZIP codes
8 ZIP Code Tabulation Areas have land in Mahnomen County; 5 of them have most of their land inside the county, and the others mainly cover neighboring areas.
5651656542565575656656589565925662156651
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 Mahnomen County
Mahnomen County shares a land border with 4 county equivalents. Each of them has more land than Mahnomen County. The largest neighbor is Polk County (1,971 mi²) and the smallest is Norman County (872.8 mi²). Together with its neighbors, Mahnomen County forms a block of 5,715.7 mi² of land, of which it holds 9.8%.
| Bordering county equivalent | Land mi² | Size vs. Mahnomen | Compare |
|---|---|---|---|
| Polk County | 1,971 | 3.5× larger | Compare |
| Becker County | 1,315 | 2.4× larger | Compare |
| Clearwater County | 999 | 1.8× larger | Compare |
| Norman County | 872.8 | 1.6× larger | Compare |
How big is Mahnomen County compared with U.S. states?
Mahnomen County has less land than any of the 50 states. Rhode Island, the smallest state by land area, has 1,033.9 mi², about 1.9 times as much. Minnesota’s county land could hold about 143 areas the size of Mahnomen County.
Another way to picture it: the same land area would fill a square about 23.6 miles (38 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 Mahnomen County?
Mahnomen County has more land than 1,364 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 Mahnomen County at #1,815 nationally by total area, 43 places closer to the top than its land rank. The water assigned to this geography moves it ahead of some county equivalents with more land.
Its water share is 4.3%, compared with a national county-equivalent median of 1.2% — 3.1 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 Mahnomen County in the national ranking. They can be in different states and are not necessarily geographic neighbors.
| Land rank | County equivalent | Land mi² | Comparison |
|---|---|---|---|
| #1857 | St. Mary Parish, Louisiana | 558.5 | Compare |
| #1858 | Mahnomen County, Minnesota | 557.9 | This county |
| #1859 | Madison County, Tennessee | 557.2 | Compare |
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.
Representative coordinates
The Census internal point is 47.328387, -95.811089. It represents a location inside the geography; it is not necessarily the centroid or the address of a courthouse.
Source and precision
U.S. Census Bureau, 2026 Gazetteer Files, Counties. Original ALAND: 1,444,868,080 m²; AWATER: 64,851,527 m². Rankings use ALAND; exact ties use ascending GEOID. Tables preserve Census-published square miles to three decimals, with conversions based on those values.
Common questions
How big is Mahnomen County?
Mahnomen County, Minnesota has 557.9 square miles (1,444.9 km²) of land and 25 square miles of water, for a total area of 582.9 square miles. It ranks #1858 of 3,222 U.S. county equivalents by land area.
Is Mahnomen County the largest county in Minnesota?
No. Mahnomen County ranks #59 of 87 in Minnesota by land area. The largest is St. Louis County, with 6,248.1 square miles of land.
What counties border Mahnomen County?
Mahnomen County shares a land border with Becker County, Clearwater County, Norman County, and Polk County.
What is the population of Mahnomen County?
The Census Bureau estimates Mahnomen County had 5,153 residents on July 1, 2025, ranking #2,886 of 3,222 county equivalents. That is 9.2 people per square mile of land.
What is the county seat of Mahnomen County?
The county seat of Mahnomen County is Mahnomen.
What cities and towns are in Mahnomen County?
Mahnomen County has 19 county subdivisions (cities, towns and townships). The most populous five are Mahnomen city, Twin Lakes township, Pembina township, Waubun city, and Island Lake township.
Is Mahnomen County part of a metropolitan area?
No. Mahnomen County is outside every metropolitan and micropolitan statistical area in the July 2023 OMB delineation.
How many ZIP codes are in Mahnomen County?
8 ZIP Code Tabulation Areas have land in Mahnomen County, and 5 of them have most of their land inside the county. Census ZIP Code Tabulation Areas approximate USPS ZIP Code areas.
How does Mahnomen County compare with U.S. states?
It has less land than every state. Rhode Island, the smallest, has 1.9 times as much land.
How many acres of land are in Mahnomen County?
The land measurement converts to approximately 357,035 acres. Including water, total area is approximately 373,060 acres. One square mile equals 640 acres.
Why might another source show a different area?
Check whether it reports land or total area, its Census vintage, and its rounding. Our guide explains how to reconcile county area figures.
Can this establish a property boundary?
No. Statistical measurements and generalized maps do not establish property lines. Consult the relevant local surveying or land-records authority.