Lewistown (also Lewis Town or Lewiston) is a census-designated place in central Washington Township, Logan County, Ohio, United States. Until the 1829 Treaty of Lewistown, the community was the site of a Shawnee settlement. It said to have been named in honor of “Captain” John Lewis, a Shawnee leader. Nearby Indian Lake was once known as the Lewistown Reservoir, after this settlement.