Snohomish County area

Population and density of Snohomish County

The Census Bureau estimates that 870,656 people lived in Snohomish County on July 1, 2025. That ranks #74 of 3,222 county equivalents nationally and #3 of 39 in Washington. Since the April 1, 2020 estimates base of 827,947, the population has grown by 42,709 (+5.2%), compared with +3.8% for Washington as a whole.

With 2,086.5 square miles of land, that is 417 people per square mile (161 per km²), placing Snohomish County #400 nationally for density and #6 in Washington. The median county equivalent has 47 people per square mile; the Washington median is 39. Put another way, there are about 1.5 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 Snohomish County

20 incorporated places lie at least partly in Snohomish County. Together they are home to 492,374 people (56.6%); the other 378,282 (43.4%) live outside any incorporated place, in unincorporated communities and rural areas.

The largest is Everett city, with 113,567 residents in the county. Among places with at least 1,000 residents in 2020, Sultan city grew fastest since then (+39.9%).

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

Metropolitan area

Snohomish County is a central county of the Seattle-Tacoma-Bellevue, WA Metropolitan Statistical Area, in the Everett, WA metropolitan division. Its 3 county equivalents have 4,161,883 residents on 5,870.3 square miles of land; Snohomish County accounts for 35.5% of the land and 20.9% of the residents. By combined land it ranks #37 of 393 metropolitan areas, and #15 by population. It belongs to the Seattle-Tacoma, WA Combined Statistical Area.

ZIP codes

30 ZIP Code Tabulation Areas have land in Snohomish County; 27 of them have most of their land inside the county, and the others mainly cover neighboring areas.

980129802098021980269803698037980439807298077980879820198203982049820798208982239824198251982529825698258982709827198272982759828298290982929829498296

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 Snohomish County

Snohomish County shares a land border with 4 county equivalents. It has more land than 2 of them. The largest neighbor is Chelan County (2,921.2 mi²) and the smallest is Island County (208.7 mi²). Together with its neighbors, Snohomish County forms a block of 9,062.4 mi² of land, of which it holds 23%.

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

Snohomish County has more land than 2 of the 50 states. It is about 1.1 times the land area of Delaware (1,948.6 mi²), while Connecticut, the next larger state, has 2.3 times as much land (4,842.5 mi²). Washington’s county land could hold about 32 areas the size of Snohomish County.

Another way to picture it: the same land area would fill a square about 45.7 miles (73.5 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 Snohomish County?

Snohomish County has more land than 2,952 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 Snohomish County at #285 nationally by total area, 15 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 5%, compared with a national county-equivalent median of 1.2% — 3.8 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 Snohomish 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.