Whatcom County area

Population and density of Whatcom County

The Census Bureau estimates that 236,392 people lived in Whatcom County on July 1, 2025. That ranks #309 of 3,222 county equivalents nationally and #9 of 39 in Washington. Since the April 1, 2020 estimates base of 226,845, the population has grown by 9,547 (+4.2%), compared with +3.8% for Washington as a whole.

With 2,107.9 square miles of land, that is 112 people per square mile (43 per km²), placing Whatcom County #921 nationally for density and #10 in Washington. The median county equivalent has 47 people per square mile; the Washington median is 39. Put another way, there are about 5.7 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 Whatcom County

7 incorporated places lie at least partly in Whatcom County. Together they are home to 144,069 people (60.9%); the other 92,323 (39.1%) live outside any incorporated place, in unincorporated communities and rural areas.

The largest is Bellingham city, with 96,395 residents in the county. Among places with at least 1,000 residents in 2020, Nooksack city grew fastest since then (+23%).

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

Metropolitan area

Whatcom County is a central county of the Bellingham, WA Metropolitan Statistical Area. Whatcom County is the area’s only county equivalent, so the metro area has the same 2,107.9 square miles of land. By combined land it ranks #149 of 393 metropolitan areas, and #206 by population.

ZIP codes

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

982209822598226982299823098237982409824498247982489826298264982669827698281982839828498295

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 Whatcom County

Whatcom County shares a land border with 2 county equivalents. It has more land than 1 of them. The largest neighbor is Okanogan County (5,266.2 mi²) and the smallest is Skagit County (1,730.2 mi²). Together with its neighbors, Whatcom County forms a block of 9,104.4 mi² of land, of which it holds 23.2%.

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

Whatcom 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 Whatcom County.

Another way to picture it: the same land area would fill a square about 45.9 miles (73.9 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 Whatcom County?

Whatcom County has more land than 2,955 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 Whatcom County at #235 nationally by total area, 32 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 15.8%, compared with a national county-equivalent median of 1.2% — 14.7 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 Whatcom 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.