Guemes Island is a small island in western Skagit County, Washington, United States. It is located north of Fidalgo Island and the city of Anacortes, and is accessible by private boat and by the Guemes Island ferry operated by Skagit County. Guemes Island was named after the Viceroy of New Spain, Juan Vicente de Güemes, who commissioned an expedition that revealed the islands to Spain in 1794.