Jefferson County area

Population and density of Jefferson County

The Census Bureau estimates that 33,970 people lived in Jefferson County on July 1, 2025. That ranks #1,378 of 3,222 county equivalents nationally and #27 of 39 in Washington. Since the April 1, 2020 estimates base of 32,972, the population has grown by 998 (+3%), compared with +3.8% for Washington as a whole.

With 1,803.7 square miles of land, that is 19 people per square mile (7.3 per km²), placing Jefferson County #2,362 nationally for density and #29 in Washington. The median county equivalent has 47 people per square mile; the Washington median is 39. Put another way, there are about 34 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 Jefferson County

1 incorporated place lies at least partly in Jefferson County. Together they are home to 10,678 people (31.4%); the other 23,292 (68.6%) live outside any incorporated place, in unincorporated communities and rural areas.

The largest is Port Townsend city, with 10,678 residents in the county.

Metropolitan area

Jefferson County is a central county of the Port Townsend, WA Micropolitan Statistical Area. Jefferson County is the area’s only county equivalent, so the micro area has the same 1,803.7 square miles of land. By combined land it ranks #90 of 542 micropolitan areas, and #405 by population.

ZIP codes

9 ZIP Code Tabulation Areas have land in Jefferson County; 8 of them have most of their land inside the county, and the others mainly cover neighboring areas.

983209832598331983399835898365983689837698382

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 Jefferson County

Jefferson County shares a land border with 3 county equivalents. It has more land than 2 of them. The largest neighbor is Grays Harbor County (1,902.3 mi²) and the smallest is Mason County (959.6 mi²). Together with its neighbors, Jefferson County forms a block of 6,404.3 mi² of land, of which it holds 28.2%.

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

Jefferson County has more land than 1 of the 50 states. It is about 1.7 times the land area of Rhode Island (1,033.9 mi²), while Delaware, the next larger state, has 1.1 times as much land (1,948.6 mi²). Washington’s county land could hold about 37 areas the size of Jefferson County.

Another way to picture it: the same land area would fill a square about 42.5 miles (68.3 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 Jefferson County?

Jefferson County has more land than 2,895 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 Jefferson County at #286 nationally by total area, 41 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 17.6%, compared with a national county-equivalent median of 1.2% — 16.4 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 Jefferson 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.