Hat Island, also known as Gedney Island, is a small island in Possession Sound in the U.S. state of Washington. The island is covered by a census-designated place (CDP) that is part of Snohomish County. The population was 41 at the 2010 census. The island lies between the mainland city of Everett, Washington, and the southern part of Whidbey Island; it has a land area of 1.768 km2.

Everett is the county seat and most populous city of Snohomish County, Washington, United States. It is 25 miles (40 km) north of Seattle and is one of the main cities in the metropolitan area and the Puget Sound region. Everett is the seventh-most populous city in the state by population, with 110,629 residents as of the 2020 census. The city is primarily situated on a peninsula at the mouth of the Snohomish River along Port Gardner Bay, an inlet of Possession Sound, and extends to the south and west.