McMicken Island Marine State Park is a public recreation area on Harstine Island in south Puget Sound, Mason County, Washington. The state park's 222 acres include 11.5 acres of forested McMicken Island and 1661 ft of saltwater shoreline with a sheltered cove. A sand bar connects McMicken Island to Harstine Island at low tide. Park activities include hiking, boating, and harvesting shellfish. The park is administered as a satellite of Jarrell Cove State Park. It bears the name of William C. McMicken, who was Washington Surveyor General from 1873 to 1886.