Benton County is one of the 36 counties in the U.S. state of Oregon. As of the 2023 census population estimates, the population was 99,355. Its county seat is Corvallis. The county was named after Thomas Hart Benton, a U.S. Senator who advocated American control over the Oregon Country. Benton County is designated as the Corvallis, OR Metropolitan Statistical Area, which is included in the Portland–Vancouver–Salem, OR–WA Combined Statistical Area. It is in the Willamette Valley.