Fairfield is a suburban city located in both Butler and Hamilton counties in the U.S. state of Ohio. Fairfield is located approximately 25 miles north of Cincinnati and is situated on the east bank of the Great Miami River. The population was 42,510 at the 2010 census. Prior to European settlement the Fairfield area was home to several Indian tribes, most prominently the Shawnee and the Miami. The prehistoric Hopewell and Adena peoples constructed numerous earthworks around the city, though most were unwittingly removed by early settlers in order to accommodate farm fields. The area that is now Fairfield was part of the original Symmes Purchase. Also known as the Miami Purchase, the region was acquired by Judge John Cleves Symmes from the Continental Congress in 1788 and included much of the land between the Little Miami and Great Miami rivers that became the present day counties of Hamilton, Butler, and Warren.