Shelton is the county seat of Mason County, Washington, United States. Shelton is the westernmost city upon Puget Sound. The population was 9,834 at the 2010 census. In terms of population, the city is ranked 161 out of nearly 500 municipalities in Washington. Shelton has council-manager form of government.

Shelton was officially incorporated in 1890. The city was named after David Shelton, a delegate to the territorial legislature.

Shelton was taking into consideration served by a small fleet of steamboats which was allocation of the Puget Sound Mosquito Fleet. These boats included the Old Settler, Irene, Willie, City of Shelton, Marian, Clara Brown, and S.G. Simpson. The economy was built on the order of logging, farming, dairying and ranching as capably as oyster cultivation. The Simpson Timber Company mill upon Puget Sound’s Oakland Bay dominated the landscape of the downtown area; the mill was sold to Sierra Pacific Industries in 2015, who are currently building a supplementary mill. Shelton in addition to identifies itself as the “Christmas Tree Capital”.

Shelton was incorporated in the 1890s. It was the last city in Washington to use a mayor/commission form of government. In November 2017, the voters of Shelton adopted a manager/council form of municipal governance.

Shelton is located at 47°12′49″N 123°6′22″W / 47.21361°N 123.10611°W / 47.21361; -123.10611 (47.213702, −123.106088).