Seattle is the most populous city in the U.S. state of Washington and in the Pacific Northwest region of North America. With a population of 755,078 in 2023, it is the 18th-most populous city in the United States. The city is the county seat of King County, the most populous county in Washington. The Seattle metropolitan area's population is 4.02 million, making it the 15th-most populous in the United States. Its growth rate of 21.1% between 2010 and 2020 made it one of the country's fastest-growing large cities.