Des Moines, Washington (Wikipedia) Des Moines (/dəˈmɔɪnz/ də-MOYNZ) is a city in King County, Washington, United States. The population was 32,888 as of the 2020 census. The city is located on the east shore of Puget Sound, near the center of the Seattle metropolitan area. It is bordered by the suburbs of Federal Way to the south, Kent to the east, SeaTac to the northeast, Burien to the north, and Normandy Park to the northwest.