Mason County Flag

Mason County

State:
Washington
County Seat:
Shelton

Mason County's 2026 population is estimated at 71,388, reflecting a 1.25% growth rate over the past year (World Population Review estimate based on U.S. Census Bureau data). Mason County is the 20th largest county in Washington. The 2010 population was 60,733 and has grown 17.54% since 2010.

71,388
Total Population
74
Population Density (mi²)
20
Population Rank (State)
878 1.25%
Annual Population Growth

Mason County Population

Demographics

Economics and Income Statistics