County outline
Where Pennington County is located
Area breakdown
Land accounts for 99.7% of Pennington County’s measured area and water for 0.3%. Its combined area converts to 1,601.1 square kilometers or approximately 395,645 acres.
Green: land · blue: water
| Measurement | Square miles | Square kilometers | Acres |
|---|---|---|---|
| Land | 616.52 | 1,596.779 | 394,572.8 |
| Water | 1.675 | 4.338 | 1,072 |
| Total | 618.195 | 1,601.118 | 395,644.8 |
How Pennington County compares
By original Census land area, Pennington County ranks #50 of 87 in Minnesota and #1570 of 3,222 nationally. National rankings include the 50 states, District of Columbia, and Puerto Rico.
Its land area is 0.914 times the Minnesota county-equivalent median of 674.6 square miles. It accounts for 0.8% of the combined county land area in the state.
See the complete Minnesota ranking · What counts as a county equivalent?
Population and density of Pennington County
The Census Bureau estimates that 13,686 people lived in Pennington County on July 1, 2025. That ranks #2,250 of 3,222 county equivalents nationally and #60 of 87 in Minnesota. Since the April 1, 2020 estimates base of 13,987, the population has declined by 301 (−2.2%), compared with +2.2% for Minnesota as a whole.
With 616.5 square miles of land, that is 22 people per square mile (8.6 per km²), placing Pennington County #2,241 nationally for density and #51 in Minnesota. The median county equivalent has 47 people per square mile; the Minnesota median is 27. Put another way, there are about 29 acres of land per resident.
| July 1 | 2020 | 2021 | 2022 | 2023 | 2024 | 2025 |
|---|---|---|---|---|---|---|
| Estimate | 13,942 | 13,786 | 13,826 | 13,734 | 13,750 | 13,686 |
| Change | — | −156 | +40 | −92 | +16 | −64 |
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 Pennington County
Pennington County is divided into 24 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 Thief River Falls city, with 8,799 residents (64.3% of the county). The largest by land is Sanders township, at 36.2 mi², or 5.9% of the county’s land.
| County subdivision | Population 2025 | Since 2020 | Land mi² | Share of county land |
|---|---|---|---|---|
| Thief River Falls cityCounty seat | 8,799 | −0.7% | 6.003 | 1% |
| Rocksbury township | 1,050 | −4.3% | 33.5 | 5.4% |
| North township | 622 | −4% | 22.7 | 3.7% |
| Smiley township | 587 | −5.6% | 36 | 5.8% |
| Norden township | 361 | −0.8% | 27.6 | 4.5% |
| Sanders township | 291 | −4% | 36.2 | 5.9% |
| St. Hilaire city | 259 | −5.5% | 0.782 | 0.1% |
| Highlanding township | 188 | −5.5% | 36.1 | 5.9% |
| River Falls township | 180 | −5.8% | 22.6 | 3.7% |
| Silverton township | 175 | −6.9% | 26.7 | 4.3% |
| Kratka township | 135 | −5.6% | 35.9 | 5.8% |
| Deer Park township | 122 | −5.4% | 23.1 | 3.7% |
| Goodridge city | 108 | −3.6% | 0.188 | 0% |
| Star township | 95 | −5.9% | 36.1 | 5.9% |
| Numedal township | 93 | −3.1% | 27.8 | 4.5% |
Show the other 9 subdivisions
| Name | Population 2025 | Since 2020 | Land mi² |
|---|---|---|---|
| Reiner township | 88 | −5.4% | 26.9 |
| Wyandotte township | 88 | −5.4% | 22.6 |
| Cloverleaf township | 87 | −5.4% | 26.9 |
| Goodridge township | 75 | −5.1% | 26.9 |
| Hickory township | 65 | −5.8% | 35.1 |
| Black River township | 62 | −6.1% | 24 |
| Polk Centre township | 61 | −6.2% | 24.1 |
| Bray township | 50 | −5.7% | 35.9 |
| Mayfield township | 45 | −6.3% | 22.9 |
Population: U.S. Census Bureau Vintage 2025 subcounty estimates, counting only the part of each subdivision inside Pennington County. Land: 2026 Census Gazetteer. How communities are listed.
Metropolitan area
Pennington 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
7 ZIP Code Tabulation Areas have land in Pennington County; 2 of them have most of their land inside the county, and the others mainly cover neighboring areas.
56684567015672556742567485675056754
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 Pennington County
Pennington County shares a land border with 5 county equivalents. It has more land than 1 of them. The largest neighbor is Beltrami County (2,504.7 mi²) and the smallest is Red Lake County (432.4 mi²). Together with its neighbors, Pennington County forms a block of 8,298.6 mi² of land, of which it holds 7.4%.
| Bordering county equivalent | Land mi² | Size vs. Pennington | Compare |
|---|---|---|---|
| Beltrami County | 2,504.7 | 4.1× larger | Compare |
| Polk County | 1,971 | 3.2× larger | Compare |
| Marshall County | 1,775.1 | 2.9× larger | Compare |
| Clearwater County | 999 | 1.6× larger | Compare |
| Red Lake County | 432.4 | 1.4× smaller | Compare |
How big is Pennington County compared with U.S. states?
Pennington County has less land than any of the 50 states. Rhode Island, the smallest state by land area, has 1,033.9 mi², about 1.7 times as much. Minnesota’s county land could hold about 129 areas the size of Pennington County.
Another way to picture it: the same land area would fill a square about 24.8 miles (40 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 Pennington County?
Pennington County has more land than 1,652 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 Pennington County at #1,685 nationally by total area, 115 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 0.3%, compared with a national county-equivalent median of 1.2% — 0.9 percentage points lower. 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 Pennington County in the national ranking. They can be in different states and are not necessarily geographic neighbors.
| Land rank | County equivalent | Land mi² | Comparison |
|---|---|---|---|
| #1569 | Hampden County, Massachusetts | 617 | Compare |
| #1570 | Pennington County, Minnesota | 616.5 | This county |
| #1571 | Cross County, Arkansas | 616.3 | 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 48.069247, -96.037725. 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: 1,596,779,066 m²; AWATER: 4,338,967 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 Pennington County?
Pennington County, Minnesota has 616.5 square miles (1,596.8 km²) of land and 1.675 square miles of water, for a total area of 618.2 square miles. It ranks #1570 of 3,222 U.S. county equivalents by land area.
Is Pennington County the largest county in Minnesota?
No. Pennington County ranks #50 of 87 in Minnesota by land area. The largest is St. Louis County, with 6,248.1 square miles of land.
What counties border Pennington County?
Pennington County shares a land border with Marshall County, Red Lake County, Polk County, Beltrami County, and Clearwater County.
What is the population of Pennington County?
The Census Bureau estimates Pennington County had 13,686 residents on July 1, 2025, ranking #2,250 of 3,222 county equivalents. That is 22 people per square mile of land.
What is the county seat of Pennington County?
The county seat of Pennington County is Thief River Falls.
What cities and towns are in Pennington County?
Pennington County has 24 county subdivisions (cities, towns and townships). The most populous five are Thief River Falls city, Rocksbury township, North township, Smiley township, and Norden township.
Is Pennington County part of a metropolitan area?
No. Pennington County is outside every metropolitan and micropolitan statistical area in the July 2023 OMB delineation.
How many ZIP codes are in Pennington County?
7 ZIP Code Tabulation Areas have land in Pennington County, and 2 of them have most of their land inside the county. Census ZIP Code Tabulation Areas approximate USPS ZIP Code areas.
How does Pennington County compare with U.S. states?
It has less land than every state. Rhode Island, the smallest, has 1.7 times as much land.
How many acres of land are in Pennington County?
The land measurement converts to approximately 394,573 acres. Including water, total area is approximately 395,645 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.