{"nrhp_refnum":"70000488","name":"Fort Jefferson Site","other_names":[],"category":"site","location":{"address":"OH 121","address_restricted":false,"city":"Fort Jefferson","county":"Darke County","state":"OH","lat":40.02543256900003,"lon":-84.64557466499997,"geom_source":"nps_gis"},"listed_date":"1970-11-10","is_nhl":false,"nhl_designated_date":null,"areas_of_significance":["Military"],"significance_levels":["state"],"summary":{"what_it_is":"Site of Fort Jefferson, a frontier military post built in October 1791 on the west side of Ohio Route 121 in Neave Township, Darke County, Ohio. It is now a state memorial with markers and a fieldstone monument.","why_significant":"The fort was built by Gen. Arthur St. Clair's army during the 1791 campaign against the Miami tribes and was named for Secretary of State Thomas Jefferson. Gen. Anthony Wayne later used it as a link in his supply chain during the victorious 1793-94 campaign that led to the Treaty of Greeneville and opened much of Ohio to settlement.","narrative":"Fort Jefferson was a small frontier fort in what is now Darke County, Ohio, built in the autumn of 1791. After Gen. Harmar's defeat by the Miami in 1790, Territorial Governor Arthur St. Clair marched north from Cincinnati, intending to destroy the Miami villages and build forts along the way. His troops reached this spot on October 13, 1791 and began construction, and by October 24 the garrison could finish the work. The fort was named for Thomas Jefferson. It measured 35 yards square with a bastion at each corner, with barracks and storerooms forming the outer walls. St. Clair left a small force and marched on to disaster on the upper Wabash River. Gen. Anthony Wayne later used the fort as a supply link in his 1793-94 campaign, which led to the Treaty of Greeneville. Nothing of the fort survives today. Markers show the original layout, a fieldstone monument stands on the site, and it has been a state memorial since 1929.","period_of_significance":"18th Century; specific date 1791","architect_builder":null,"architectural_style":null,"criteria":[],"status_note":"Nothing remains of the original fort; markers show the locations of the outer walls, powder magazine and bullock pen, and a fieldstone monument has been erected. The site is a state memorial administered by the Ohio Historical Society.","vacant_flag":null,"machine_generated":true,"model":"claude-sonnet-5-5","prompt_version":"v1.0-2026-10-29","generated_at":"2026-10-29 02:53:10.370072-05","source_pdf":"https://s3.amazonaws.com/NARAprodstorage/lz/electronic-records/rg-079/NPS_OH/70000488.pdf"},"photo":{"url_800":"https://nationalhistoricalregister.com/media/70000488/46427ecc48-800.webp","url_1600":"https://nationalhistoricalregister.com/media/70000488/46427ecc48-1600.webp","licence":"Public domain","author":"Nyttend","credit_html":"<a href=\"https://commons.wikimedia.org/wiki/File:Fort_Jefferson_site_in_Ohio.jpg\" rel=\"noopener\">Nyttend</a>, Public domain, via Wikimedia Commons","source_page":"https://commons.wikimedia.org/wiki/File:Fort_Jefferson_site_in_Ohio.jpg"},"district":null,"sources":{"nps_snapshot_date":"2026-05-22","nara_catalog":"https://catalog.archives.gov/id/71988001","wikipedia":"https://en.wikipedia.org/wiki/Fort_Jefferson_(Ohio)","wikidata":"https://www.wikidata.org/wiki/Q8564748"},"indexable":true,"url":"https://nationalhistoricalregister.com/ohio/darke-county/fort-jefferson-site-70000488/"}