County outline
Where St. Croix County is located
Area breakdown
Land accounts for 98.2% of St. Croix County’s measured area and water for 1.8%. Its combined area converts to 1,904.1 square kilometers or approximately 470,518 acres.
Green: land · blue: water
| Measurement | Square miles | Square kilometers | Acres |
|---|---|---|---|
| Land | 722.158 | 1,870.381 | 462,181.1 |
| Water | 13.027 | 33.74 | 8,337.3 |
| Total | 735.185 | 1,904.12 | 470,518.4 |
How St. Croix County compares
By original Census land area, St. Croix County ranks #39 of 72 in Wisconsin and #1237 of 3,222 nationally. National rankings include the 50 states, District of Columbia, and Puerto Rico.
Its land area is 0.959 times the Wisconsin county-equivalent median of 753 square miles. It accounts for 1.3% of the combined county land area in the state.
See the complete Wisconsin ranking · What counts as a county equivalent?
Population and density of St. Croix County
The Census Bureau estimates that 98,276 people lived in St. Croix County on July 1, 2025. That ranks #641 of 3,222 county equivalents nationally and #17 of 72 in Wisconsin. Since the April 1, 2020 estimates base of 93,534, the population has grown by 4,742 (+5.1%), compared with +1.3% for Wisconsin as a whole.
With 722.2 square miles of land, that is 136 people per square mile (53 per km²), placing St. Croix County #821 nationally for density and #20 in Wisconsin. The median county equivalent has 47 people per square mile; the Wisconsin median is 51. Put another way, there are about 4.7 acres of land per resident.
| July 1 | 2020 | 2021 | 2022 | 2023 | 2024 | 2025 |
|---|---|---|---|---|---|---|
| Estimate | 93,875 | 95,016 | 96,116 | 96,976 | 97,654 | 98,276 |
| Change | — | +1,141 | +1,100 | +860 | +678 | +622 |
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 St. Croix County
St. Croix County is divided into 35 cities and towns. In Wisconsin, county subdivisions are local governments, and together they cover all of the county’s land and residents.
The most populous is Hudson city, with 15,019 residents (15.3% of the county). The largest by land is Somerset town, at 46.3 mi², or 6.4% of the county’s land. Among those with at least 1,000 residents in 2020, River Falls city grew fastest since then (+37.5%).
| County subdivision | Population 2025 | Since 2020 | Land mi² | Share of county land |
|---|---|---|---|---|
| Hudson cityCounty seat | 15,019 | +1.8% | 6.825 | 0.9% |
| New Richmond city | 10,988 | +8.9% | 11.8 | 1.6% |
| Hudson townCounty seat | 8,736 | +0.7% | 24.4 | 3.4% |
| Troy town | 5,686 | +2.9% | 36.2 | 5% |
| River Falls city | 5,002 | +37.5% | 3.402 | 0.5% |
| Somerset town | 4,536 | +5.8% | 46.3 | 6.4% |
| St. Joseph town | 4,408 | +5.2% | 32.1 | 4.4% |
| Baldwin village | 4,347 | +1.4% | 3.324 | 0.5% |
| Richmond town | 4,276 | +5.1% | 30.8 | 4.3% |
| North Hudson village | 3,803 | +0.1% | 1.564 | 0.2% |
| Star Prairie town | 3,771 | +1.2% | 28.9 | 4% |
| Somerset village | 3,408 | +13% | 3.318 | 0.5% |
| Hammond town | 2,732 | +8% | 32.5 | 4.5% |
| Roberts village | 2,493 | +29.6% | 3.015 | 0.4% |
| Hammond village | 1,857 | −2.6% | 2.16 | 0.3% |
Show the other 20 subdivisions
| Name | Population 2025 | Since 2020 | Land mi² |
|---|---|---|---|
| Warren town | 1,830 | +5.8% | 32.4 |
| Kinnickinnic town | 1,827 | +1.1% | 35 |
| Woodville village | 1,389 | +0.1% | 1.793 |
| Eau Galle town | 1,256 | +0.8% | 32.7 |
| Glenwood City city | 1,254 | −3.7% | 3.467 |
| Baldwin town | 1,056 | +1.1% | 32.2 |
| Springfield town | 1,010 | +1.1% | 34.1 |
| Cady town | 916 | +3.7% | 34.6 |
| Stanton town | 890 | −1.4% | 32.2 |
| Emerald town | 850 | +1.7% | 34.9 |
| Glenwood town | 752 | 0% | 33.2 |
| Cylon town | 700 | −1.3% | 35.2 |
| Erin Prairie town | 668 | −0.1% | 35.4 |
| Star Prairie village | 656 | −2.8% | 2.143 |
| Forest town | 638 | +0.3% | 37.2 |
| Pleasant Valley town | 570 | +0.7% | 18.1 |
| Rush River town | 491 | −1.2% | 17.5 |
| Deer Park village | 243 | −3.2% | 0.898 |
| Wilson village | 202 | −2.9% | 1.706 |
| Spring Valley village | 16 | −5.9% | 0.844 |
Population: U.S. Census Bureau Vintage 2025 subcounty estimates, counting only the part of each subdivision inside St. Croix County. Land: 2026 Census Gazetteer. How communities are listed.
Metropolitan area
St. Croix County is an outlying county of the Minneapolis-St. Paul-Bloomington, MN-WI Metropolitan Statistical Area. Its 15 county equivalents have 3,790,295 residents on 7,047.6 square miles of land; St. Croix County accounts for 10.2% of the land and 2.6% of the residents. By combined land it ranks #26 of 393 metropolitan areas, and #16 by population. It belongs to the Minneapolis-St. Paul, MN-WI Combined Statistical Area.
| County equivalent | Population 2025 | Land mi² |
|---|---|---|
| Hennepin CountyMinnesota | 1,284,784 | 554 |
| Ramsey CountyMinnesota | 541,623 | 152.3 |
| Dakota CountyMinnesota | 457,710 | 562.6 |
| Anoka CountyMinnesota | 381,605 | 422 |
| Washington CountyMinnesota | 286,895 | 384.8 |
| Scott CountyMinnesota | 159,017 | 356.1 |
| Wright CountyMinnesota | 157,559 | 661.2 |
| Carver CountyMinnesota | 114,379 | 353.9 |
| Sherburne CountyMinnesota | 104,194 | 432.9 |
| St. Croix County | 98,276 | 722.2 |
| Chisago CountyMinnesota | 59,142 | 414.9 |
| Isanti CountyMinnesota | 44,386 | 435.8 |
| Pierce County | 43,519 | 574 |
| Le Sueur CountyMinnesota | 29,453 | 448.8 |
| Mille Lacs CountyMinnesota | 27,753 | 572.3 |
ZIP codes
18 ZIP Code Tabulation Areas have land in St. Croix County; 11 of them have most of their land inside the county, and the others mainly cover neighboring areas.
540025400554007540135401554016540175402054022540235402554026540275402854082547345474954767
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 St. Croix County
St. Croix County shares a land border with 4 county equivalents, including 1 in Minnesota. It has more land than 2 of them. The largest neighbor is Polk County (914.3 mi²) and the smallest is Washington County (384.8 mi²). Together with its neighbors, St. Croix County forms a block of 3,445.4 mi² of land, of which it holds 21%.
| Bordering county equivalent | Land mi² | Size vs. St. Croix | Compare |
|---|---|---|---|
| Polk County | 914.3 | 1.3× larger | Compare |
| Dunn County | 850.2 | 1.2× larger | Compare |
| Pierce County | 574 | 1.3× smaller | Compare |
| Washington CountyMinnesota | 384.8 | 1.9× smaller | Compare |
How big is St. Croix County compared with U.S. states?
St. Croix County has less land than any of the 50 states. Rhode Island, the smallest state by land area, has 1,033.9 mi², about 1.4 times as much. Wisconsin’s county land could hold about 75 areas the size of St. Croix County.
Another way to picture it: the same land area would fill a square about 26.9 miles (43.2 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 St. Croix County?
St. Croix County has more land than 1,985 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 St. Croix County at #1,311 nationally by total area, 74 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 1.8%, compared with a national county-equivalent median of 1.2% — 0.6 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 St. Croix County in the national ranking. They can be in different states and are not necessarily geographic neighbors.
| Land rank | County equivalent | Land mi² | Comparison |
|---|---|---|---|
| #1236 | Oliver County, North Dakota | 722.4 | Compare |
| #1237 | St. Croix County, Wisconsin | 722.2 | This county |
| #1238 | Latimer County, Oklahoma | 722.1 | 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 45.028959, -92.447284. 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: 1,870,380,152 m²; AWATER: 33,740,053 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 St. Croix County?
St. Croix County, Wisconsin has 722.2 square miles (1,870.4 km²) of land and 13 square miles of water, for a total area of 735.2 square miles. It ranks #1237 of 3,222 U.S. county equivalents by land area.
Is St. Croix County the largest county in Wisconsin?
No. St. Croix County ranks #39 of 72 in Wisconsin by land area. The largest is Marathon County, with 1,545.2 square miles of land.
What counties border St. Croix County?
St. Croix County shares a land border with Pierce County, Polk County, Dunn County, and Washington County, Minnesota.
What is the population of St. Croix County?
The Census Bureau estimates St. Croix County had 98,276 residents on July 1, 2025, ranking #641 of 3,222 county equivalents. That is 136 people per square mile of land.
What is the county seat of St. Croix County?
The county seat of St. Croix County is Hudson.
What cities and towns are in St. Croix County?
St. Croix County has 35 county subdivisions (cities, towns and townships). The most populous five are Hudson city, New Richmond city, Hudson town, Troy town, and River Falls city.
Is St. Croix County part of a metropolitan area?
Yes. It is an outlying county of the Minneapolis-St. Paul-Bloomington, MN-WI Metropolitan Statistical Area, which has 15 county equivalents and 3,790,295 residents.
How many ZIP codes are in St. Croix County?
18 ZIP Code Tabulation Areas have land in St. Croix County, and 11 of them have most of their land inside the county. Census ZIP Code Tabulation Areas approximate USPS ZIP Code areas.
How does St. Croix County compare with U.S. states?
It has less land than every state. Rhode Island, the smallest, has 1.4 times as much land.
How many acres of land are in St. Croix County?
The land measurement converts to approximately 462,181 acres. Including water, total area is approximately 470,518 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.