Des Moines (/dəˈmɔɪnz/ US dict: də·moinz′) is a city in King County, Washington, United States. The population was 29,673 at the 2010 census.Des Moines is located on the east shore of Puget Sound, approximately halfway between the major cities of Seattle and Tacoma. The city is bordered by the suburbs of Federal Way to the south, Kent to the east, Sea-Tac to the northeast, Burien to the north, and Normandy Park to the northwest.