Fort Ancient is a collection of American Indian mounds and fortifications located in Washington Township, Warren County, Ohio, along the eastern shore of the Little Miami River about seven miles southeast of Lebanon on State Route 350. It was built by the Hopewell Indians, who lived in the area from the first century B.C. to the Sixth Century A.D. and the Fort Ancient Indians, who lived there from the Eleventh Century to the Fifteenth Century. There are some three and one-half miles of walls there on a bluff 270 feet above the Little Miami. The state of Ohio purchased the land to become Ohio's first state park.