Benton County was created on December 23, 1847, by an act of the Provisional Government of Oregon. The county was
 named after Democratic Senator Thomas Hart Benton of Missouri, an advocate of the doctrine of Manifest Destiny and the
 belief that the American government should control the whole of the Oregon Country. At the time of its formation the county
 included all the country west of the Willamette River, south of Polk County and running all the way to the California border
 in the south and the Pacific Ocean in the west.

 The county was created out of lands originally inhabited by the Klickitat, who rented it from the Kalapuyas for use as
 hunting grounds. All aboriginal claims to land within Benton County were ceded in the Treaty of Dayton in 1855. Portions
 of  Benton County were taken to form Coos, Curry, Douglas, Jackson, Josephine, Lane and Lincoln Counties, leaving Benton
 County in its present form.

 The city of Marysville, later renamed Corvallis, was made the county seat in 1851. The city briefly was the capital of
 Oregon.  In 1862 Corvallis became the site of the Oregon State Agricultural College, known today as Oregon State
 University.