Washington County area

Population and density of Washington County

The Census Bureau estimates that 129,795 people lived in Washington County on July 1, 2025. That ranks #513 of 3,222 county equivalents nationally and #3 of 5 in Rhode Island. Since the April 1, 2020 estimates base of 129,832, the population has declined by 37 (−0%), compared with +1.6% for Rhode Island as a whole.

With 329.3 square miles of land, that is 394 people per square mile (152 per km²), placing Washington County #413 nationally for density and #5 in Rhode Island. The median county equivalent has 47 people per square mile; the Rhode Island median is 1,029. Put another way, there are about 1.6 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 9 cities and towns. In Rhode Island, county subdivisions are local governments, and together they cover all of the county’s land and residents.

The most populous is South Kingstown town, with 32,009 residents (24.7% of the county). The largest by land is Exeter town, at 57.5 mi², or 17.4% of the county’s land. Among those with at least 1,000 residents in 2020, Richmond town grew fastest since then (+1.3%).

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 Providence-Warwick, RI-MA Metropolitan Statistical Area. Its 6 county equivalents have 1,708,161 residents on 1,587 square miles of land; Washington County accounts for 20.7% of the land and 7.6% of the residents. By combined land it ranks #211 of 393 metropolitan areas, and #40 by population. It belongs to the Boston-Worcester-Providence, MA-RI-NH Combined Statistical Area.

ZIP codes

20 ZIP Code Tabulation Areas have land in Washington County, and each lies mostly inside the county.

0280402807028080281202813028220283202833028360285202873028740287502879028810288202891028920289402898

ZIP Code Tabulation Areas are the Census Bureau’s approximations of USPS ZIP Code service areas, from the 2020 Census relationship files. Post-office-box and single-address ZIP Codes have no tabulation area.

Counties bordering Washington County

Washington County shares a land border with 3 county equivalents, including 2 in Connecticut. It has more land than 1 of them. The largest neighbor is Southeastern Connecticut Planning Region (598.1 mi²) and the smallest is Kent County (168.6 mi²). Together with its neighbors, Washington County forms a block of 1,649.9 mi² of land, of which it holds 20%.

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 3.1 times as much. Rhode Island’s county land could hold about 3.1 areas the size of Washington County.

Another way to picture it: the same land area would fill a square about 18.1 miles (29.2 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 Washington County?

Washington County has more land than 483 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 #1,965 nationally by total area, 774 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 41.5%, compared with a national county-equivalent median of 1.2% — 40.3 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.