 Despite this, there are a number of pockets where the Republican Party often wins marginal majorities.The Cascade area (approximately a population of 17,000), which included much of unincorporated Benson Hill north of SE 200 Street and west of 128th Avenue SE, voted to be annexed by the city of Renton in 2007, effective March 1, 2008.The remaining unincorporated area of King County, which is primarily the Fairwood community, has the option of annexing to the city of Renton or incorporating as a city.