Bothell /ˈbɒθəl/ BOTH-əl is a city located in King and Snohomish Counties in the State of Washington. It is part of the Seattle metropolitan area. The population was 33,505 as of the 2010 census. Prior to annexation and the 2000 census, the northern portions of Bothell that lie within Snohomish County were considered a part of the Alderwood Manor-Bothell North census-designated place.