Benton County is located in the northwest part of the U.S. state of Indiana, along the border with Illinois. As of 2020, the county's population was 8,719. It contains six incorporated towns as well as several small unincorporated settlements; it is divided into 11 townships which provide local services. The county seat is Fowler. Benton County is part of the Lafayette, Indiana metropolitan area.

The lands of present NW Indiana were explored by French explorer Robert de LaSalle. At that time the area was inhabited by the Miami Confederation of Indians. Through White settlement, encroachment, and confrontation, the various indigenous groups were forced to cede their claim to the area. In October 1818, the Pottawattamies, Weas, and Delawares ceded their lands west of the Tippecanoe River to the government. In a treaty dated October 23, 1826, the Pottawattamie and Miamis ceded all their lands east of the Tippecanoe. A treaty dated October 26, 1832, with the Pottawattamie ceded control of the northwestern part of Indiana; on October 27 the Pottawattamie of Indiana and Michigan also relinquished all claim to any remaining land in those states.

Before 1832, this area was not open to settlement; previous settlers had taken the southern parts of Ohio, Indiana and Illinois. Northwestern Indiana was also less desirable for farming, being described as alternate swamps, sterile sand ridges and flat, wet prairies, although it did proliferate in game.

A state legislative act dated February 7, 1835, created two counties in this area, Newton and Jasper. The county governments were not created at that time and the counties were attached to White County for administrative purposes. The Jasper County organization was effected beginning March 15, 1838. On February 18, 1840, the county of Benton was formed from Jasper's area. It was named for Thomas H. Benton (D), U.S. Senator from Missouri. The original county seat selected in 1843 was Oxford, but after a long struggle between contending factions it was moved to Fowler in 1874.

The current Benton County courthouse, located in Fowler, was designed by Gurdon P. Randall of Chicago and built in 1874 by Levi L. Leach at a cost of $62,257. The new courthouse was an impressive building from an architectural standpoint, but also provided much-needed improvements in security, including large fire-proof vaults. Randall had designed the Marshall County courthouse a few years earlier.

In 2008 the Benton County Wind Farm began operating with 87 1.5 MW wind turbines. Duke Energy purchases electricity from the wind farm and sells it to customers through its GoGreen program.

In 2009 the Fowler Ridge Wind Farm opened nearby, giving Benton County one of the largest concentrations of wind turbines in the United States east of the Mississippi River.

Benton County lies along the state's western border with Illinois. It consists of low rolling hills, with all available terrain devoted to agriculture or development. Data gathered from space shuttle measurements list the county's lowest elevation as 138 meters (453 feet) and its highest elevation as 240 meters (790 feet). However, a knoll 4 miles (6.4 km) NNW of Boswell is shown on official topographic maps as 915 feet (279 meters) ASL.