St. Joseph County area

Population and density of St. Joseph County

The Census Bureau estimates that 272,861 people lived in St. Joseph County on July 1, 2025. That ranks #273 of 3,222 county equivalents nationally and #5 of 92 in Indiana. Since the April 1, 2020 estimates base of 272,910, the population has declined by 49 (−0%), compared with +2.8% for Indiana as a whole.

With 457.8 square miles of land, that is 596 people per square mile (230 per km²), placing St. Joseph County #294 nationally for density and #6 in Indiana. The median county equivalent has 47 people per square mile; the Indiana median is 88. Put another way, there are about 1.1 acres of land per resident.

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

9 incorporated places lie at least partly in St. Joseph County. Together they are home to 164,435 people (60.3%); the other 108,426 (39.7%) live outside any incorporated place, in unincorporated communities and rural areas.

The largest is South Bend city, with 103,201 residents in the county. Among places with at least 1,000 residents in 2020, Mishawaka city grew fastest since then (+0.2%).

Population: U.S. Census Bureau Vintage 2025 subcounty estimates, counting only the part of each place inside St. Joseph County. Land: 2026 Census Gazetteer, for the whole place even where it extends into other counties. How communities are listed.

Metropolitan area

St. Joseph County is a central county of the South Bend-Mishawaka, IN-MI Metropolitan Statistical Area. Its 2 county equivalents have 324,538 residents on 947.9 square miles of land; St. Joseph County accounts for 48.3% of the land and 84.1% of the residents. By combined land it ranks #285 of 393 metropolitan areas, and #165 by population. It belongs to the South Bend-Elkhart-Mishawaka, IN-MI Combined Statistical Area.

ZIP codes

25 ZIP Code Tabulation Areas have land in St. Joseph County; 20 of them have most of their land inside the county, and the others mainly cover neighboring areas.

46506465304653646544465454655046552465544655646561465634657346574465954660146613466144661546616466174661946624466284663546637

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 6 county equivalents, including 2 in Michigan. It has more land than 2 of them. The largest neighbor is LaPorte County (598.3 mi²) and the smallest is Starke County (309.1 mi²). Together with its neighbors, St. Joseph County forms a block of 3,330 mi² of land, of which it holds 13.7%.

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 2.3 times as much. Indiana’s county land could hold about 78 areas the size of St. Joseph County.

Another way to picture it: the same land area would fill a square about 21.4 miles (34.4 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 982 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 #2,312 nationally by total area, 72 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 0.8%, compared with a national county-equivalent median of 1.2% — 0.4 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 St. Joseph County in the national ranking. They can be in different states and are not necessarily geographic neighbors.

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.