Washington County area

Population and density of Washington County

The Census Bureau estimates that 286,895 people lived in Washington County on July 1, 2025. That ranks #256 of 3,222 county equivalents nationally and #5 of 87 in Minnesota. Since the April 1, 2020 estimates base of 267,565, the population has grown by 19,330 (+7.2%), compared with +2.2% for Minnesota as a whole.

With 384.8 square miles of land, that is 746 people per square mile (288 per km²), placing Washington County #248 nationally for density and #5 in Minnesota. The median county equivalent has 47 people per square mile; the Minnesota median is 27. Put another way, there are about 0.858 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 Washington County

Washington County is divided into 33 municipalities and townships. In Minnesota, county subdivisions are local governments, and together they cover all of the county’s land and residents; a few are unorganized areas without their own government.

The most populous is Woodbury city, with 81,558 residents (28.4% of the county), and it is also the largest by land at 34.9 mi². The county seat, Stillwater city, has 19,354 residents. Among those with at least 1,000 residents in 2020, Newport city grew fastest since then (+45.5%).

Population: U.S. Census Bureau Vintage 2025 subcounty estimates, counting only the part of each subdivision inside Washington County. Land: 2026 Census Gazetteer. How communities are listed.

Metropolitan area

Washington County is a central 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; Washington County accounts for 5.5% of the land and 7.6% 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.

ZIP codes

19 ZIP Code Tabulation Areas have land in Washington County; 16 of them have most of their land inside the county, and the others mainly cover neighboring areas.

55001550035501655025550335503855042550435504755055550715507355082550905511055115551255512855129

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 Washington County

Washington County shares a land border with 7 county equivalents, including 3 in Wisconsin. It has more land than 1 of them. The largest neighbor is Polk County (914.3 mi²) and the smallest is Ramsey County (152.3 mi²). Together with its neighbors, Washington County forms a block of 4,147 mi² of land, of which it holds 9.3%.

How big is Washington County compared with U.S. states?

Washington County has less land than any of the 50 states. Rhode Island, the smallest state by land area, has 1,033.9 mi², about 2.7 times as much. Minnesota’s county land could hold about 207 areas the size of Washington County.

Another way to picture it: the same land area would fill a square about 19.6 miles (31.6 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 Washington County?

Washington County has more land than 636 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 Washington County at #2,475 nationally by total area, 111 places closer to the top than its land rank. The water assigned to this geography moves it ahead of some county equivalents with more land.

Its water share is 9.1%, compared with a national county-equivalent median of 1.2% — 7.9 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 Washington 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.