Mason County, Washington
County seat: Shelton · Population 71,165 (2025) · 960 sq mi
Mason County is the 20th most populous of Washington's 39 counties, with 71,165 people (2025 estimate). Its county seat is Shelton. The map shows its 1 city or town and the 5 neighboring counties.
Mason County facts
- County seat
- Shelton
- Population (2025 estimate)
- 71,165 +8.3% since 2020
- Land area
- 960 sq mi 29th largest of 39
- Water area
- 92 sq mi
- Population density
- 74 per sq mi
- Established
- 1854
- Same name
- One of 6 Mason Counties in the US
- Named after
- Charles H. Mason American politician (1830-1859)
- Largest city
- Shelton 10,921
- Median household income
- $83,270
- Cities and towns
- 1 plus 6 CDPs
- ZIP codes
- 15
- Time zone
- Pacific
- FIPS code
- 53045
Cities and towns in Mason County
Mason County has 1 incorporated place. Populations count the people living inside Mason County; cities that cross a county line also list the other counties.
| Name | Type | Population 2025 | Also in |
|---|---|---|---|
| Shelton (county seat) | City | 10,921 |
Unincorporated communities (CDPs)
Census-designated places are communities without their own city government; the county provides their services.
| Community | Population | Also in |
|---|---|---|
| Belfair | 4,557 | |
| Allyn | 2,404 | |
| Grapeview | 1,088 | |
| Skokomish | 560 | |
| Union | 457 | |
| Hoodsport | 216 |
ZIP codes in Mason County
15 ZIP codes reach into Mason County. ZIP codes ignore county lines, so some also cover a neighboring county.
- 98312 also Kitsap County
- 98380 also Kitsap County
- 98502 also Thurston County
- 98524
- 98528 also Kitsap County
- 98541 also Grays Harbor County
- 98546
- 98548
- 98555
- 98557 also Grays Harbor County
- 98560
- 98563 also Grays Harbor County
- 98584
- 98588
- 98592
Population of Mason County, 2020–2025
Mason County grew by 5,444 people (+8.3%) between April 2020 and July 2025: 938 more deaths than births and a net gain of 6,443 people from migration.
| Year (July 1) | Population |
|---|---|
| 2020 | 66,041 |
| 2021 | 67,271 |
| 2022 | 68,244 |
| 2023 | 68,768 |
| 2024 | 69,759 |
| 2025 | 71,165 |
Neighboring counties
- Grays Harbor County southwest · 78,144 people
- Jefferson County northwest · 33,970 people
- Kitsap County northeast · 283,374 people
- Thurston County southeast · 304,261 people
- Pierce County southeast · 946,288 people
Printable Mason 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) (113 KB)
- PNG (2400 px) (106 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.
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