Benton County was created from Polk County by an act of the Provisional Government of Oregon in 1847. It is one of seven counties in the United States to be named after Senator Thomas Hart Benton of Missouri, a longtime advocate of the development of the Oregon Territory. The county was created out of an area originally inhabited by the Klickitat Indians, who rented it from the Kalapuya Indians for use as hunting grounds. At that time, the boundaries began at the intersection of Polk County and the Willamette River, ran as far south as the California border and as far west as the Pacific Ocean. Later, portions of Benton County were taken to form Coos, Curry, Douglas, Jackson, Josephine, Lane and Lincoln Counties, leaving it in its present form with 679 square miles of land area. In Benton County there are five incorporated cities (Corvallis, Philomath, Monroe, Adair Village and North Albany) and five officially designated unincorporated communities (Alsea, Wren, Alpine, Bellfountain and Greenberry).