San Joaquin County area

Population and density of San Joaquin County

The Census Bureau estimates that 823,815 people lived in San Joaquin County on July 1, 2025. That ranks #80 of 3,222 county equivalents nationally and #14 of 58 in California. Since the April 1, 2020 estimates base of 779,234, the population has grown by 44,581 (+5.7%), compared with −0.5% for California as a whole.

With 1,392.3 square miles of land, that is 592 people per square mile (228 per km²), placing San Joaquin County #297 nationally for density and #10 in California. The median county equivalent has 47 people per square mile; the California median is 112. 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 San Joaquin County

8 incorporated places lie at least partly in San Joaquin County. Together they are home to 683,923 people (83%); the other 139,892 (17%) live outside any incorporated place, in unincorporated communities and rural areas.

The largest is Stockton city, with 324,597 residents in the county. Among places with at least 1,000 residents in 2020, Lathrop city grew fastest since then (+48.9%).

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

Metropolitan area

San Joaquin County is a central county of the Stockton-Lodi, CA Metropolitan Statistical Area. San Joaquin County is the area’s only county equivalent, so the metro area has the same 1,392.3 square miles of land. By combined land it ranks #232 of 393 metropolitan areas, and #78 by population. It belongs to the San Jose-San Francisco-Oakland, CA Combined Statistical Area.

ZIP codes

37 ZIP Code Tabulation Areas have land in San Joaquin County; 30 of them have most of their land inside the county, and the others mainly cover neighboring areas.

94505952029520395204952059520695207952099521095211952129521595219952209522795230952319523695237952409524295253952589530495320953309533695337953619536695376953779538595391956329564195686

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 San Joaquin County

San Joaquin County shares a land border with 6 county equivalents. It has more land than 5 of them. The largest neighbor is Stanislaus County (1,496.2 mi²) and the smallest is Amador County (594.6 mi²). Together with its neighbors, San Joaquin County forms a block of 6,922.8 mi² of land, of which it holds 20.1%.

How big is San Joaquin County compared with U.S. states?

San Joaquin County has more land than 1 of the 50 states. It is about 1.3 times the land area of Rhode Island (1,033.9 mi²), while Delaware, the next larger state, has 1.4 times as much land (1,948.6 mi²). California’s county land could hold about 112 areas the size of San Joaquin County.

Another way to picture it: the same land area would fill a square about 37.3 miles (60.1 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 San Joaquin County?

San Joaquin County has more land than 2,788 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 San Joaquin County at #484 nationally by total area, 50 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 2.4%, compared with a national county-equivalent median of 1.2% — 1.2 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 San Joaquin 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.