Admission to Fort Jefferson is free.
- Open: Daily during daylight hours
- Location: (Map It) Weavers-Fort Jefferson Rd. in Greenville, Ohio
- Phone: 937-547-7370 or 844-288-7708
- Web: click here
Fort Jefferson is in Fort Jefferson, Ohio near Greenville, Ohio was built in 1791. This fort served as an outpost to General Arthur St. Clair, and its purpose was to shelter army supplies and guard against nearby Indians. It was abandoned in 1796 and is now a park with a monument, twenty feet high, marking the site where it once stood.