Oak Hills is a census-designated place and neighborhood in Washington County, Oregon, United States. The CDP population was 11,903 at the 2020 census. It is on unincorporated land north of Beaverton, west of Cedar Mill, and south/southeast of Bethany. The CDP is roughly bounded by the Sunset Highway on the south, West Union Road on the north, Northwest 174th Avenue on the west, and Northwest 143rd Avenue on the east. The U.S. Postal Service has assigned Beaverton addresses to the area.