San Juan County, Washington
County seat: Friday Harbor · Population 18,577 (2025) · 174 sq mi
San Juan County is the 32nd most populous of Washington's 39 counties, with 18,577 people (2025 estimate). Its county seat is Friday Harbor. The map shows its 1 city or town and the 5 neighboring counties.
San Juan County facts
- County seat
- Friday Harbor
- Population (2025 estimate)
- 18,577 +4.5% since 2020
- Land area
- 174 sq mi 39th largest of 39
- Water area
- 447 sq mi
- Population density
- 107 per sq mi
- Established
- 1873
- Same name
- One of 4 San Juan Counties in the US
- Named after
- San Juan Islands island group in Washington State, USA
- Largest city
- Friday Harbor 2,729
- Median household income
- $84,800
- Cities and towns
- 1 plus 1 CDPs
- ZIP codes
- 10
- Time zone
- Pacific
- FIPS code
- 53055
Cities and towns in San Juan County
San Juan County has 1 incorporated place. Populations count the people living inside San Juan County; cities that cross a county line also list the other counties.
| Name | Type | Population 2025 | Also in |
|---|---|---|---|
| Friday Harbor (county seat) | Town | 2,729 |
Unincorporated communities (CDPs)
Census-designated places are communities without their own city government; the county provides their services.
| Community | Population | Also in |
|---|---|---|
| Roche Harbor | 778 |
ZIP codes in San Juan County
10 ZIP codes reach into San Juan County. ZIP codes ignore county lines, so some also cover a neighboring county.
- 98221 also Skagit County
- 98222
- 98243
- 98245
- 98250
- 98261
- 98279
- 98280
- 98286
- 98297
Population of San Juan County, 2020–2025
San Juan County grew by 791 people (+4.5%) between April 2020 and July 2025: 304 more deaths than births and a net gain of 1,160 people from migration.
| Year (July 1) | Population |
|---|---|
| 2020 | 17,825 |
| 2021 | 18,629 |
| 2022 | 18,668 |
| 2023 | 18,563 |
| 2024 | 18,556 |
| 2025 | 18,577 |
Neighboring counties
- Whatcom County east · 236,392 people
- Skagit County east · 132,975 people
- Clallam County southwest · 78,202 people
- Island County southeast · 85,657 people
- Jefferson County south · 33,970 people
Printable San Juan County map
The PDF is a vector file with real text: it prints sharp on Letter paper and you can search it for a town. The PNG is 2400 pixels wide for slides and documents. Both are free to use with a credit to WhichCounty.
- PDF (Letter) (94 KB)
- PNG (2400 px) (123 KB)
Paste this code to embed the map on your site:
Sources
- Boundaries: U.S. Census Bureau, 2025 Cartographic Boundary Files (1:500,000).
- Population: Census Bureau county and city estimates, Vintage 2025. CDP populations: American Community Survey 2020–2024.
- Places and ZIP codes: Census Bureau 2026 Gazetteer and 2020 ZIP Code Tabulation Area relationship files.
- County seat, founding year and name origin: Wikidata (CC0), checked against state sources.
Back to the Washington county map with all 39 counties. Found an error? Tell us.