Renton is bordered to the north by Newcastle. Along the east side of Renton is the Urban Growth Boundary established by King County, as such there is no incorporated city directly east of Renton. The geographical characteristics of Renton's eastern border are varied and include (from north to south) the south flank of Cougar Mountain descending southward merging with the community of May Valley. The terrain then elevates south of May Valley to the communities of the East Renton Plateau before descending to the north bank of the Cedar River. Renton is bordered to the south by the city of Kent. The western border consists of the city of Tukwila, and finally the unincorporated King County community West Hill and Lake Washington to the northwest.