County outline
Where Stanislaus County is located
Area breakdown
Land accounts for 98.8% of Stanislaus County’s measured area and water for 1.2%. Its combined area converts to 3,921.4 square kilometers or approximately 968,996 acres.
Green: land · blue: water
| Measurement | Square miles | Square kilometers | Acres |
|---|---|---|---|
| Land | 1,496.15 | 3,875.011 | 957,536 |
| Water | 17.907 | 46.379 | 11,460.5 |
| Total | 1,514.057 | 3,921.39 | 968,996.5 |
How Stanislaus County compares
By original Census land area, Stanislaus County ranks #30 of 58 in California and #402 of 3,222 nationally. National rankings include the 50 states, District of Columbia, and Puerto Rico.
Its land area is 0.974 times the California county-equivalent median of 1,535.7 square miles. It accounts for 1% of the combined county land area in the state.
See the complete California ranking · What counts as a county equivalent?
Population and density of Stanislaus County
The Census Bureau estimates that 557,719 people lived in Stanislaus County on July 1, 2025. That ranks #130 of 3,222 county equivalents nationally and #16 of 58 in California. Since the April 1, 2020 estimates base of 553,284, the population has grown by 4,435 (+0.8%), compared with −0.5% for California as a whole.
With 1,496.2 square miles of land, that is 373 people per square mile (144 per km²), placing Stanislaus County #435 nationally for density and #15 in California. The median county equivalent has 47 people per square mile; the California median is 112. Put another way, there are about 1.7 acres of land per resident.
| July 1 | 2020 | 2021 | 2022 | 2023 | 2024 | 2025 |
|---|---|---|---|---|---|---|
| Estimate | 553,702 | 553,047 | 552,453 | 554,459 | 557,372 | 557,719 |
| Change | — | −655 | −594 | +2,006 | +2,913 | +347 |
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 Stanislaus County
9 incorporated places lie at least partly in Stanislaus County. Together they are home to 447,650 people (80.3%); the other 110,069 (19.7%) live outside any incorporated place, in unincorporated communities and rural areas.
The largest is Modesto city, with 219,652 residents in the county. Among places with at least 1,000 residents in 2020, Patterson city grew fastest since then (+11.8%).
| Incorporated place | Population 2025 | Since 2020 | Land mi² |
|---|---|---|---|
| Modesto cityCounty seat | 219,652 | +0.5% | 43.7 |
| Turlock city | 72,864 | +0.3% | 16.8 |
| Ceres city | 48,982 | −1.5% | 9.499 |
| Patterson city | 26,587 | +11.8% | 9.917 |
| Riverbank city | 26,557 | +6.5% | 4.71 |
| Oakdale city | 23,246 | +0.3% | 6.225 |
| Newman city | 12,453 | +0.5% | 2.149 |
| Waterford city | 9,258 | +1.4% | 2.358 |
| Hughson city | 8,051 | +7.7% | 1.916 |
Population: U.S. Census Bureau Vintage 2025 subcounty estimates, counting only the part of each place inside Stanislaus County. Land: 2026 Census Gazetteer, for the whole place even where it extends into other counties. How communities are listed.
Metropolitan area
Stanislaus County is a central county of the Modesto, CA Metropolitan Statistical Area. Stanislaus County is the area’s only county equivalent, so the metro area has the same 1,496.2 square miles of land. By combined land it ranks #219 of 393 metropolitan areas, and #107 by population. It belongs to the San Jose-San Francisco-Oakland, CA Combined Statistical Area.
ZIP codes
28 ZIP Code Tabulation Areas have land in Stanislaus County; 24 of them have most of their land inside the county, and the others mainly cover neighboring areas.
95230953049530795313953169531995322953239532695328953299535095351953549535595356953579535895360953619536395367953689538095382953859538695387
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 Stanislaus County
Stanislaus County shares a land border with 5 county equivalents. It has more land than 3 of them. The largest neighbor is Tuolumne County (2,220.9 mi²) and the smallest is Calaveras County (1,020 mi²). Together with its neighbors, Stanislaus County forms a block of 9,358.5 mi² of land, of which it holds 16%.
| Bordering county equivalent | Land mi² | Size vs. Stanislaus | Compare |
|---|---|---|---|
| Tuolumne County | 2,220.9 | 1.5× larger | Compare |
| Merced County | 1,938 | 1.3× larger | Compare |
| San Joaquin County | 1,392.3 | 1.1× smaller | Compare |
| Santa Clara County | 1,291.1 | 1.2× smaller | Compare |
| Calaveras County | 1,020 | 1.5× smaller | Compare |
How big is Stanislaus County compared with U.S. states?
Stanislaus County has more land than 1 of the 50 states. It is about 1.4 times the land area of Rhode Island (1,033.9 mi²), while Delaware, the next larger state, has 1.3 times as much land (1,948.6 mi²). California’s county land could hold about 104 areas the size of Stanislaus County.
Another way to picture it: the same land area would fill a square about 38.7 miles (62.2 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 Stanislaus County?
Stanislaus County has more land than 2,820 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 Stanislaus County at #441 nationally by total area, 39 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 1.2%, 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 Stanislaus County in the national ranking. They can be in different states and are not necessarily geographic neighbors.
| Land rank | County equivalent | Land mi² | Comparison |
|---|---|---|---|
| #401 | Deaf Smith County, Texas | 1,496.8 | Compare |
| #402 | Stanislaus County, California | 1,496.2 | This county |
| #403 | Barnes County, North Dakota | 1,491.6 | 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 37.562252, -121.002796. 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: 3,875,011,026 m²; AWATER: 46,378,777 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 Stanislaus County?
Stanislaus County, California has 1,496.2 square miles (3,875 km²) of land and 17.9 square miles of water, for a total area of 1,514.1 square miles. It ranks #402 of 3,222 U.S. county equivalents by land area.
Is Stanislaus County the largest county in California?
No. Stanislaus County ranks #30 of 58 in California by land area. The largest is San Bernardino County, with 20,068.4 square miles of land.
What counties border Stanislaus County?
Stanislaus County shares a land border with San Joaquin County, Merced County, Santa Clara County, Calaveras County, and Tuolumne County.
What is the population of Stanislaus County?
The Census Bureau estimates Stanislaus County had 557,719 residents on July 1, 2025, ranking #130 of 3,222 county equivalents. That is 373 people per square mile of land.
What is the county seat of Stanislaus County?
The county seat of Stanislaus County is Modesto.
What cities and towns are in Stanislaus County?
Stanislaus County has 9 incorporated places. The most populous five are Modesto city, Turlock city, Ceres city, Patterson city, and Riverbank city; 110,069 residents live outside any incorporated place.
Is Stanislaus County part of a metropolitan area?
Yes. It is a central county of the Modesto, CA Metropolitan Statistical Area.
How many ZIP codes are in Stanislaus County?
28 ZIP Code Tabulation Areas have land in Stanislaus County, and 24 of them have most of their land inside the county. Census ZIP Code Tabulation Areas approximate USPS ZIP Code areas.
How does Stanislaus County compare with U.S. states?
It has more land than 1 of the 50 states, including Rhode Island (1,033.9 square miles of land).
How many acres of land are in Stanislaus County?
The land measurement converts to approximately 957,536 acres. Including water, total area is approximately 968,996 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.