Watonwan County area

Watonwan County, Minnesota covers 439.7 square miles: 435 square miles of land and 4.783 square miles of water. Its county seat is St. James. An estimated 11,459 people lived there in 2025.

Official Census measurements · GEOID 271652026 Gazetteer · retrieved September 27, 2026
Land area435 mi²
Water area4.783 mi²
Population (2025)11,459
People per mi²26

County outline

Generalized outline of Watonwan County, Minnesota
2025 Census cartographic boundary, fitted to this frame. County maps are not at a common scale. The 2026 area measurements below come from the separate Gazetteer release. Map source and limitations.

Where Watonwan County is located

Watonwan County highlighted on a map of all U.S. county equivalents. About the maps

Area breakdown

Land accounts for 98.9% of Watonwan County’s measured area and water for 1.1%. Its combined area converts to 1,138.9 square kilometers or approximately 281,429 acres.

Green: land · blue: water

MeasurementSquare milesSquare kilometersAcres
Land434.951,126.515278,368
Water4.78312.3883,061.1
Total439.7331,138.903281,429.1

How Watonwan County compares

By original Census land area, Watonwan County ranks #76 of 87 in Minnesota and #2330 of 3,222 nationally. National rankings include the 50 states, District of Columbia, and Puerto Rico.

Its land area is 0.645 times the Minnesota county-equivalent median of 674.6 square miles. It accounts for 0.5% of the combined county land area in the state.

See the complete Minnesota ranking · What counts as a county equivalent?

Population and density of Watonwan County

The Census Bureau estimates that 11,459 people lived in Watonwan County on July 1, 2025. That ranks #2,392 of 3,222 county equivalents nationally and #63 of 87 in Minnesota. Since the April 1, 2020 estimates base of 11,254, the population has grown by 205 (+1.8%), compared with +2.2% for Minnesota as a whole.

With 435 square miles of land, that is 26 people per square mile (10 per km²), placing Watonwan County #2,108 nationally for density and #47 in Minnesota. The median county equivalent has 47 people per square mile; the Minnesota median is 27. Put another way, there are about 24 acres of land per resident.

Estimated population, 2020–2025 · line scaled to this county’s own range
July 1202020212022202320242025
Estimate11,23611,15811,24311,23711,36511,459
Change—−78+85−6+128+94

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 Watonwan County

Watonwan County is divided into 20 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 St. James city, with 4,863 residents (42.4% of the county). The largest by land is South Branch township, at 39.1 mi², or 9% of the county’s land. Among those with at least 1,000 residents in 2020, Madelia city grew fastest since then (+3.5%).

County subdivisionPopulation 2025Since 2020Land mi²Share of county land
St. James cityCounty seat4,863+1%2.3270.5%
Madelia city2,488+3.5%1.520.3%
Butterfield city611+1.7%0.3920.1%
Long Lake township345+2.1%34.57.9%
Madelia township307+1.7%33.37.6%
Riverdale township291+1.7%38.98.9%
Rosendale township277+1.5%38.28.8%
Antrim township272+2.6%35.78.2%
South Branch township256+1.6%39.19%
Nelson township242+1.7%35.68.2%
St. James townshipCounty seat231+1.8%33.57.7%
Lewisville city208+1.5%0.2560.1%
Fieldon township207+1.5%35.78.2%
Butterfield township203+1.5%35.58.2%
Odin township168+1.8%34.78%
Show the other 5 subdivisions
NamePopulation 2025Since 2020Land mi²
Adrian township131+1.6%34.9
Odin city127+1.6%0.375
Darfur city840%0.231
La Salle city75+1.4%0.078
Ormsby city73+4.3%0.189

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

Metropolitan area

Watonwan 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

10 ZIP Code Tabulation Areas have land in Watonwan County; 6 of them have most of their land inside the county, and the others mainly cover neighboring areas.

56019560225605656060560625608156088561205616056162

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 Watonwan County

Watonwan County shares a land border with 4 county equivalents. Each of them has more land than Watonwan County. The largest neighbor is Blue Earth County (747.8 mi²) and the smallest is Brown County (611.3 mi²). Together with its neighbors, Watonwan County forms a block of 3,146.4 mi² of land, of which it holds 13.8%.

Map of Watonwan County and the 4 county equivalents that border it Brown County, Minnesota: 611.3 mi² landMartin County, Minnesota: 712.3 mi² landCottonwood County, Minnesota: 640 mi² landBlue Earth County, Minnesota: 747.8 mi² land
Watonwan County (dark) and its bordering county equivalents. Select a neighbor to open its profile. Drawn from the 2025 Census cartographic boundaries in an equal-area projection. How borders are determined.
Bordering county equivalentLand mi²Size vs. WatonwanCompare
Blue Earth County747.81.7× largerCompare
Martin County712.31.6× largerCompare
Cottonwood County6401.5× largerCompare
Brown County611.31.4× largerCompare

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

Watonwan County has less land than any of the 50 states. Rhode Island, the smallest state by land area, has 1,033.9 mi², about 2.4 times as much. Minnesota’s county land could hold about 183 areas the size of Watonwan County.

Land area: Watonwan County and the closest-sized states
Watonwan County435 mi²
Rhode Island1,033.9 mi²

Another way to picture it: the same land area would fill a square about 20.9 miles (33.6 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 Watonwan County?

Watonwan County has more land than 892 of the other 3,221 county equivalents in the dataset.

Land area compared with the typical county equivalent
Watonwan County435 mi²
Minnesota median674.6 mi²
National median604.5 mi²

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 Watonwan County at #2,388 nationally by total area, 58 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 1.1%, compared with a national county-equivalent median of 1.2%. The two percentages are within 0.1 percentage points of each other. 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 Watonwan County in the national ranking. They can be in different states and are not necessarily geographic neighbors.

Land rankCounty equivalentLand mi²Comparison
#2329Grundy County, Missouri435.3Compare
#2330Watonwan County, Minnesota435This county
#2331Winnebago County, Wisconsin434.7Compare

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 43.978131, -94.613906. 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: 1,126,514,006 m²; AWATER: 12,387,607 m². Rankings use ALAND; exact ties use ascending GEOID. Tables preserve Census-published square miles to three decimals, with conversions based on those values.

Download the official county source ZIP ↗ · Methodology

Common questions

How big is Watonwan County?

Watonwan County, Minnesota has 435 square miles (1,126.5 km²) of land and 4.783 square miles of water, for a total area of 439.7 square miles. It ranks #2330 of 3,222 U.S. county equivalents by land area.

Is Watonwan County the largest county in Minnesota?

No. Watonwan County ranks #76 of 87 in Minnesota by land area. The largest is St. Louis County, with 6,248.1 square miles of land.

What counties border Watonwan County?

Watonwan County shares a land border with Brown County, Martin County, Cottonwood County, and Blue Earth County.

What is the population of Watonwan County?

The Census Bureau estimates Watonwan County had 11,459 residents on July 1, 2025, ranking #2,392 of 3,222 county equivalents. That is 26 people per square mile of land.

What is the county seat of Watonwan County?

The county seat of Watonwan County is St. James.

What cities and towns are in Watonwan County?

Watonwan County has 20 county subdivisions (cities, towns and townships). The most populous five are St. James city, Madelia city, Butterfield city, Long Lake township, and Madelia township.

Is Watonwan County part of a metropolitan area?

No. Watonwan County is outside every metropolitan and micropolitan statistical area in the July 2023 OMB delineation.

How many ZIP codes are in Watonwan County?

10 ZIP Code Tabulation Areas have land in Watonwan County, and 6 of them have most of their land inside the county. Census ZIP Code Tabulation Areas approximate USPS ZIP Code areas.

How does Watonwan County compare with U.S. states?

It has less land than every state. Rhode Island, the smallest, has 2.4 times as much land.

How many acres of land are in Watonwan County?

The land measurement converts to approximately 278,368 acres. Including water, total area is approximately 281,429 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.

Cite this county

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