The Seattle metropolitan area is located in the U.S. state of Washington and includes King, Snohomish, and Pierce counties within the Puget Sound region. The United States Census Bureau officially defines the metropolitan area as the Seattle–Tacoma–Bellevue, WA Metropolitan Statistical Area, with an estimated population of 3,610,105, which is more than half of Washington's population , making it the 15th largest Metropolitan Statistical Area in the United States.