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
Mason County Courthouse
Peak of Mount Ellinor in the Olympic Mountains of Mason County
Mount Rainier over the Totten Inlet Mason County, Washington
State Route 106 is a Washington state highway in Mason County, extending 20.09 miles from U.S. Route 101 in Skokomish to SR 3 south of Belfair. The road was once a section of State Road 21 in 1915, wh