County outline
Where St. Joseph County is located
Area breakdown
Land accounts for 96.1% of St. Joseph County’s measured area and water for 3.9%. Its combined area converts to 1,349.5 square kilometers or approximately 333,457 acres.
Green: land · blue: water
| Measurement | Square miles | Square kilometers | Acres |
|---|---|---|---|
| Land | 500.639 | 1,296.649 | 320,409 |
| Water | 20.387 | 52.802 | 13,047.7 |
| Total | 521.026 | 1,349.451 | 333,456.6 |
How St. Joseph County compares
By original Census land area, St. Joseph County ranks #72 of 83 in Michigan and #2079 of 3,222 nationally. National rankings include the 50 states, District of Columbia, and Puerto Rico.
Its land area is 0.882 times the Michigan county-equivalent median of 567.8 square miles. It accounts for 0.9% of the combined county land area in the state.
See the complete Michigan ranking · What counts as a county equivalent?
Population and density of St. Joseph County
The Census Bureau estimates that 60,968 people lived in St. Joseph County on July 1, 2025. That ranks #897 of 3,222 county equivalents nationally and #33 of 83 in Michigan. Since the April 1, 2020 estimates base of 60,926, the population has grown by 42 (+0.1%), compared with +0.5% for Michigan as a whole.
With 500.6 square miles of land, that is 122 people per square mile (47 per km²), placing St. Joseph County #869 nationally for density and #28 in Michigan. The median county equivalent has 47 people per square mile; the Michigan median is 62. Put another way, there are about 5.3 acres of land per resident.
| July 1 | 2020 | 2021 | 2022 | 2023 | 2024 | 2025 |
|---|---|---|---|---|---|---|
| Estimate | 60,923 | 60,849 | 60,777 | 60,953 | 61,023 | 60,968 |
| Change | — | −74 | −72 | +176 | +70 | −55 |
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. Joseph County
St. Joseph County is divided into 18 municipalities and townships. In Michigan, county subdivisions are local governments, and together they cover all of the county’s land and residents.
The most populous is Sturgis city, with 10,900 residents (17.9% of the county). The largest by land is Nottawa township, at 35.6 mi², or 7.1% of the county’s land. Among those with at least 1,000 residents in 2020, White Pigeon township grew fastest since then (+3.6%).
| County subdivision | Population 2025 | Since 2020 | Land mi² | Share of county land |
|---|---|---|---|---|
| Sturgis city | 10,900 | −2.1% | 7.065 | 1.4% |
| Three Rivers city | 7,910 | −0.9% | 5.591 | 1.1% |
| Constantine township | 4,043 | −0.2% | 34.5 | 6.9% |
| White Pigeon township | 3,893 | +3.6% | 25.1 | 5% |
| Lockport township | 3,825 | +2.7% | 28.5 | 5.7% |
| Nottawa township | 3,808 | +3.4% | 35.6 | 7.1% |
| Sherman township | 3,462 | +0.4% | 33 | 6.6% |
| Colon township | 3,336 | +0.2% | 34.4 | 6.9% |
| Fabius township | 3,325 | +0.5% | 32 | 6.4% |
| Burr Oak township | 2,635 | +0.2% | 35.3 | 7% |
| Mendon township | 2,565 | −0.5% | 34.9 | 7% |
| Park township | 2,374 | −0.7% | 34.9 | 7% |
| Sturgis township | 2,022 | −1.2% | 17.3 | 3.5% |
| Flowerfield township | 1,607 | +0.8% | 35.5 | 7.1% |
| Fawn River township | 1,527 | +0.3% | 19 | 3.8% |
Show the other 3 subdivisions
| Name | Population 2025 | Since 2020 | Land mi² |
|---|---|---|---|
| Mottville township | 1,436 | −0.2% | 19.3 |
| Leonidas township | 1,158 | +0.1% | 35.5 |
| Florence township | 1,142 | −0.8% | 33.2 |
Population: U.S. Census Bureau Vintage 2025 subcounty estimates, counting only the part of each subdivision inside St. Joseph County. Land: 2026 Census Gazetteer. How communities are listed.
Metropolitan area
St. Joseph County is a central county of the Sturgis, MI Micropolitan Statistical Area. St. Joseph County is the area’s only county equivalent, so the micro area has the same 500.6 square miles of land. By combined land it ranks #434 of 542 micropolitan areas, and #159 by population. It belongs to the Kalamazoo-Battle Creek-Portage, MI Combined Statistical Area.
ZIP codes
13 ZIP Code Tabulation Areas have land in St. Joseph County; 10 of them have most of their land inside the county, and the others mainly cover neighboring areas.
49011490304903249040490424906649067490724907549091490934909749099
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. Joseph County
St. Joseph County shares a land border with 5 county equivalents, including 2 in Indiana. It has more land than 3 of them. The largest neighbor is Kalamazoo County (562 mi²) and the smallest is LaGrange County (379.6 mi²). Together with its neighbors, St. Joseph County forms a block of 2,901.9 mi² of land, of which it holds 17.3%.
| Bordering county equivalent | Land mi² | Size vs. St. Joseph | Compare |
|---|---|---|---|
| Kalamazoo County | 562 | 1.1× larger | Compare |
| Branch County | 506.4 | about the same | Compare |
| Cass County | 490.1 | about the same | Compare |
| Elkhart CountyIndiana | 463.2 | 1.1× smaller | Compare |
| LaGrange CountyIndiana | 379.6 | 1.3× smaller | Compare |
How big is St. Joseph County compared with U.S. states?
St. Joseph County has less land than any of the 50 states. Rhode Island, the smallest state by land area, has 1,033.9 mi², about 2.1 times as much. Michigan’s county land could hold about 113 areas the size of St. Joseph County.
Another way to picture it: the same land area would fill a square about 22.4 miles (36 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. Joseph County?
St. Joseph County has more land than 1,143 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. Joseph County at #2,101 nationally by total area, 22 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 3.9%, compared with a national county-equivalent median of 1.2% — 2.7 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. Joseph County in the national ranking. They can be in different states and are not necessarily geographic neighbors.
| Land rank | County equivalent | Land mi² | Comparison |
|---|---|---|---|
| #2078 | Edgefield County, South Carolina | 500.7 | Compare |
| #2079 | St. Joseph County, Michigan | 500.6 | This county |
| #2080 | Floyd County, Iowa | 500.6 | 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 41.911488, -85.522870. 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: 1,296,649,454 m²; AWATER: 52,802,551 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. Joseph County?
St. Joseph County, Michigan has 500.6 square miles (1,296.6 km²) of land and 20.4 square miles of water, for a total area of 521 square miles. It ranks #2079 of 3,222 U.S. county equivalents by land area.
Is St. Joseph County the largest county in Michigan?
No. St. Joseph County ranks #72 of 83 in Michigan by land area. The largest is Marquette County, with 1,809.1 square miles of land.
What counties border St. Joseph County?
St. Joseph County shares a land border with Kalamazoo County, Cass County, Branch County, LaGrange County, Indiana, and Elkhart County, Indiana.
What is the population of St. Joseph County?
The Census Bureau estimates St. Joseph County had 60,968 residents on July 1, 2025, ranking #897 of 3,222 county equivalents. That is 122 people per square mile of land.
What is the county seat of St. Joseph County?
The county seat of St. Joseph County is Centreville.
What cities and towns are in St. Joseph County?
St. Joseph County has 18 county subdivisions (cities, towns and townships). The most populous five are Sturgis city, Three Rivers city, Constantine township, White Pigeon township, and Lockport township.
Is St. Joseph County part of a metropolitan area?
Yes. It is a central county of the Sturgis, MI Micropolitan Statistical Area.
How many ZIP codes are in St. Joseph County?
13 ZIP Code Tabulation Areas have land in St. Joseph County, and 10 of them have most of their land inside the county. Census ZIP Code Tabulation Areas approximate USPS ZIP Code areas.
How does St. Joseph County compare with U.S. states?
It has less land than every state. Rhode Island, the smallest, has 2.1 times as much land.
How many acres of land are in St. Joseph County?
The land measurement converts to approximately 320,409 acres. Including water, total area is approximately 333,457 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.