County Maps US

Mason County, Washington

A county in Washington, ranked 20 of 39 by population.

CountyFIPS 53045

Within Washington
Mason County, highlighted, with the areas around it. Boundaries generalised from the 2025 Census cartographic boundary file; neighbour fills carry no data. The dot marks Shelton, the county seat, located via the 2025 Census Gazetteer.

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Population
71,165
+5,124 (+7.8%) since 2020
Land area
959.6
square miles. A further 8.7% of the total area is water
Population density
74.2
people per square mile, computed rather than published
County seat
Shelton
Seat of county government.
Established
1854
171 years ago
Largest city
Shelton city
Population 10,921.

Sources: US Census Bureau, Population Estimates Program, Vintage 2025 Population Estimates, released 26 March 2026; US Census Bureau, Gazetteer Files, 2025 Gazetteer Files, released 10 September 2025; Wikidata (CC0), Wikidata. Retrieved 30 August 2026.

Satellite view

Aerial imagery of Mason County with its boundary drawn on top. A map shows you the shape; this shows you what is inside it, and which side of the line a place falls on.

Aerial view of Mason County, Washington from the USGS National Map, with its boundary outlined
Imagery: USGS National Map, USGS Imagery Only, public domain, requested from USGS by your browser when you reach this point on the page, at 736 by 800 pixels. The boundary is the 2025 Census cartographic boundary file, reprojected to Web Mercator to match the imagery. You can also open the USGS National Map viewer.

Where Mason County ranks

Position among the 39 counties of Washington, and among all 3,144 US counties and county-equivalents. Computed from the figures on this page.

MeasureValueIn WashingtonNationally
Population71,16520th of 39781st of 3,144
Land area959.6 sq mi29th of 39731st of 3,144
Population density74.2 per sq mi15th of 391,139th of 3,144
Median household income$83,27013th of 39476th of 3,143

Full data for Mason County

Every figure below is attributed to the Census Bureau product it came from, with the vintage of that product.
MeasureValueSource and vintage
Population71,165Vintage 2025 Population Estimates
Population in 202066,041Vintage 2025 Population Estimates
2020 estimates base?65,721Vintage 2025 Population Estimates
Land area959.6 sq mi2025 Gazetteer Files
Water area91.5 sq mi2025 Gazetteer Files
Total area1,051 sq mi2025 Gazetteer Files
Population density?74.2 per sq miComputed: Vintage 2025 estimates divided by 2025 Gazetteer land area
Median household income$83,270American Community Survey 2020-2024 5-Year Estimates
Median home value$411,800American Community Survey 2020-2024 5-Year Estimates
Median age44.7American Community Survey 2020-2024 5-Year Estimates
Households26,029American Community Survey 2020-2024 5-Year Estimates
Housing units34,152American Community Survey 2020-2024 5-Year Estimates

Sources: US Census Bureau, Population Estimates Program, Vintage 2025 Population Estimates, released 26 March 2026; US Census Bureau, Gazetteer Files, 2025 Gazetteer Files, released 10 September 2025; US Census Bureau, American Community Survey, American Community Survey 2020-2024 5-Year Estimates, released 29 January 2026. Population density is computed here, not published: it divides the Vintage 2025 population estimate by the 2025 Gazetteer land area, which are two different Census products. Retrieved 30 August 2026.

How the population changed

The Census Bureau publishes the components behind an estimate, not just the total. For the year to July 2025:

Births minus deaths
-183
677 births, 860 deaths
Net migration
+1,609
More people moved in than moved out.

Source: US Census Bureau, Population Estimates Program, Vintage 2025 Population Estimates, released 26 March 2026. Retrieved 30 August 2026.

The 5 areas bordering Mason County

Ordered by the length of the border actually shared, which the Census Bureau publishes in its county adjacency file and which no other county reference presents.

Bordering areaStateShared borderPopulation
Grays Harbor CountyWashington44 mi78,144
Jefferson CountyWashington32 mi33,970
Kitsap CountyWashington27 mi283,374
Thurston CountyWashington25 mi304,261
Pierce CountyWashington16 mi946,288

Source: US Census Bureau, County Adjacency File, 2025 County Adjacency File, released 15 September 2025. Retrieved 30 August 2026.

All 39 counties of Washington

Open the interactive Washington county map, or jump straight to any of them.

Data on this page last rebuilt 30 August 2026. How these figures are produced.