Mason County
Also known as Mason County, Washington, Mason County, WA
county in the state of Washington, United States
Key facts
- Country
- United States
- State
- Washington
- Founded
- March 13, 1854
- Named after
- Charles H. Mason
- Seat
- Shelton
- Largest city
- Shelton
- Total
- 1,051 sq mi (2,720 km )
- Land
- 959 sq mi (2,480 km )
- Water
- 92 sq mi (240 km ) 8.7%
- Estimate 2025
- 71,165
- Density
- 63/sq mi (24/km )
- Time zone
- UTC−8 ( Pacific )
- Summer dst
- UTC−7 ( PDT )
~7 min read
Article
Mason County is a county located in the U.S. state of Washington. As of the 2020 census, the population was 65,726. The county seat and only incorporated city is Shelton. The county was formed out of Thurston County on March 13, 1854. Originally named Sawamish County, it took its present name in 1864 in honor of Charles H. Mason, the first Secretary of Washington Territory.
Mason County comprises the Shelton micropolitan statistical area and is included in the Seattle-Tacoma combined statistical area.