{"nrhp_refnum":"74001422","name":"Cowan Creek Circular Enclosure","other_names":[],"category":"site","location":{"address":"SW of Wilmington","address_restricted":false,"city":"Wilmington","county":"Clinton County","state":"OH","lat":39.39006762500003,"lon":-83.91015534799999,"geom_source":"nps_gis"},"listed_date":"1974-07-15","is_nhl":false,"nhl_designated_date":null,"areas_of_significance":["Prehistoric"],"significance_levels":["local"],"summary":{"what_it_is":"A prehistoric circular earthen enclosure about 90 feet in diameter within Cowan Creek State Park, Vernon Township, Clinton County, Ohio, roughly 5.5 miles southwest of Wilmington. It sits on a promontory on the north side of Cowan Lake.","why_significant":"The enclosure is closely related to the nearby Cowan Creek Mound, a Late Adena site excavated in 1949, and lies about 300 feet from it. Similar circles are noted beside Adena mounds or house sites elsewhere, such as the Green Fort Works in Vinton County. Its link to a mound that was very significant for studying Ohio's Adena people adds to its importance.","narrative":"Cowan Creek Circular Enclosure is a prehistoric earthen circle about 90 feet across, located on a bluff-edged promontory on the north side of Cowan Lake in Cowan Creek State Park, Clinton County, Ohio. It was first noticed in 1949 in aerial photographs taken of the nearby Cowan Creek Mound, which was excavated before the reservoir flooded. The mound, about 300 feet away, proved to be Late Adena, with 17 log tombs and a burned house 45 feet in diameter beneath it. The circle sat on higher ground and escaped inundation. Long cultivation reduced its height until it was barely visible, and plant growth now hides it. Similar circles occur beside Adena mounds or house sites elsewhere, including the Green Fort Works in Vinton County. Because of its association with the mound, the enclosure is considered important for understanding Ohio's Adena people. A three-acre area was nominated in case a habitation area is present.","period_of_significance":"A.D. 100-600","architect_builder":null,"architectural_style":null,"criteria":[],"status_note":"Condition marked fair and altered; the field was long cultivated and the area is now overgrown with secondary growth, making the site impossible to locate without specific knowledge. No testing has been done. State-owned park land, unoccupied.","vacant_flag":null,"machine_generated":true,"model":"claude-sonnet-5-5","prompt_version":"v1.0-2026-10-29","generated_at":"2026-10-29 02:53:09.787627-05","source_pdf":"https://s3.amazonaws.com/NARAprodstorage/lz/electronic-records/rg-079/NPS_OH/74001422.pdf"},"photo":{"url_800":"https://nationalhistoricalregister.com/media/74001422/5c5b190f22-800.webp","url_1600":"https://nationalhistoricalregister.com/media/74001422/5c5b190f22-1600.webp","licence":"Public domain","author":"Nyttend","credit_html":"<a href=\"https://commons.wikimedia.org/wiki/File:Cowan_Creek_Circular_Enclosure.jpg\" rel=\"noopener\">Nyttend</a>, Public domain, via Wikimedia Commons","source_page":"https://commons.wikimedia.org/wiki/File:Cowan_Creek_Circular_Enclosure.jpg"},"district":null,"sources":{"nps_snapshot_date":"2026-05-22","nara_catalog":"https://catalog.archives.gov/id/71987160","wikipedia":"https://en.wikipedia.org/wiki/Cowan_Creek_Circular_Enclosure","wikidata":"https://www.wikidata.org/wiki/Q14653048"},"indexable":true,"url":"https://nationalhistoricalregister.com/ohio/clinton-county/cowan-creek-circular-enclosure-74001422/"}