Mercer County's location on the east bank of the Mississippi River has made it an attractive site for habitation for thousands of years. Prior to the arrival of European settlers, Native Americans of the Sauk (Sac) tribe were drawn here because of the abundance of fish and wild game. The formal organization of Mercer County began when the Northwest Territory was created in 1787. Then, in 1812, the area was included in the Military Tract, designated by Congress as bounty land to be given as payment to soldiers who served in the War of 1812. The first settlers arrived in the 1820s via the Mississippi River or covered wagon, and Mercer County was established in 1835. Primarily an agricultural area, it has also been home to business and commerce. A variety of interesting individuals have lived in or influenced the county, including an oil baron, a baseball Hall of Famer, a country music star, and a young surveyor who one day became president.