Auburn is a city in King County, Washington, United States (with a small portion crossing into neighboring Pierce County). The population was 70,180 at the 2010 United States Census. Auburn is a suburb in the Seattle metropolitan area, and is currently ranked as the 15th largest city in the state of Washington.
Auburn is bordered by the cities of Federal Way, Pacific, and Algona to the west, Sumner to the south, Kent to the north, and unincorporated King County to the east. The Muckleshoot Indian Reservation lies to the south and southeast.