Burien is a suburban city in King County, Washington, United States, located south of Seattle on Puget Sound. As of the 2020 census, Buri…Burien is a suburban city in King County, Washington, United States, located south of Seattle on Puget Sound. As of the 2020 census, Burien's population was 52,066, which is a 56.3% increase since incorporation in 1993, making it the 25th most populous city in Washington. An annexation in 2010 increased the city's population significantly.