Coupeville is a town on Whidbey Island, in Island County, Washington, United States. It is the county seat of Island County. The population was 1,942 at the 2020 census. Prior to European settlement, Coupeville and the bay in which it is located, Penn Cove, was inhabited by the Lower Skagit, a Lushootseed-speaking Coast Salish people. There were thr…Coupeville is a town on Whidbey Island, in Island County, Washington, United States. It is the county seat of Island County. The population was 1,942 at the 2020 census. Prior to European settlement, Coupeville and the bay in which it is located, Penn Cove, was inhabited by the Lower Skagit, a Lushootseed-speaking Coast Salish people. There were three villages around the bay, with the largest being at bəc̓adᶻali, meaning "snake place", the site of present day Coupeville. There was an abundance of salmon, clams, and other resources, as well as offering easy access to the water, making it an excellent village site.