{"nrhp_refnum":"74001621","name":"Horseshoe Mound","other_names":["Portsmouth Group"],"category":"site","location":{"address":"Within Mound Park","address_restricted":false,"city":"Portsmouth","county":"Scioto County","state":"OH","lat":38.74329222600005,"lon":-82.97700182599993,"geom_source":"nps_gis"},"listed_date":"1974-05-02","is_nhl":false,"nhl_designated_date":null,"areas_of_significance":["Prehistoric"],"significance_levels":["state"],"summary":{"what_it_is":"A U-shaped (horseshoe-shaped) earthen embankment in Mound Park on Hutchins Avenue between Grant and 17th avenues in Portsmouth, Scioto County, Ohio. It is the surviving Ohio remnant of a prehistoric earthwork complex called the Portsmouth Group.","why_significant":"It is all that remains in Ohio of the Portsmouth Group, described as one of the most impressive prehistoric works in the Ohio Valley. The complex was probably a ceremonial center used during the Hopewell Phase. The whole park was nominated because rises within it may be bases of other mounds shown on the 1848 Squier and Davis map.","narrative":"Horseshoe Mound is a U-shaped earthen embankment in Mound Park, off Hutchins Avenue in Portsmouth, Ohio. The embankment is 30 to 33 feet wide at the base and 7.5 feet high, enclosing an interior 75 feet across and 178 feet long. It has probably been reconstructed and is well maintained by the city. The mound is the only surviving Ohio piece of the Portsmouth Group, a large prehistoric complex near the meeting of the Scioto and Ohio rivers. The group once included two horseshoe-shaped embankments, circles, crescents, mounds and parallel walls stretching about eight miles, linked to two large geometric works in Kentucky. It was probably built over a long period and used as a ceremonial center during the Hopewell Phase, 400 B.C. to A.D. 700. Several rises elsewhere in the park may mark other mounds shown on an 1848 map, so the whole park, about 8.25 acres, was included to help preserve what remains.","period_of_significance":"400 B.C. to A.D. 700","architect_builder":null,"architectural_style":null,"criteria":[],"status_note":"Described as in excellent condition and well maintained in a municipal park; probably reconstructed. The form checks the status as unoccupied and the present use as park.","vacant_flag":null,"machine_generated":true,"model":"claude-sonnet-5-5","prompt_version":"v1.0-2026-10-29","generated_at":"2026-10-29 02:53:09.242918-05","source_pdf":"https://s3.amazonaws.com/NARAprodstorage/lz/electronic-records/rg-079/NPS_OH/74001621.pdf"},"photo":{"url_800":"https://nationalhistoricalregister.com/media/74001621/d3632d52af-800.webp","url_1600":"https://nationalhistoricalregister.com/media/74001621/d3632d52af-1600.webp","licence":"Public domain","author":"Nyttend","credit_html":"<a href=\"https://commons.wikimedia.org/wiki/File:Horseshoe_Mound_in_Portsmouth.jpg\" rel=\"noopener\">Nyttend</a>, Public domain, via Wikimedia Commons","source_page":"https://commons.wikimedia.org/wiki/File:Horseshoe_Mound_in_Portsmouth.jpg"},"district":null,"sources":{"nps_snapshot_date":"2026-05-22","nara_catalog":"https://catalog.archives.gov/id/71991246","wikipedia":null,"wikidata":"https://www.wikidata.org/wiki/Q116268128"},"indexable":true,"url":"https://nationalhistoricalregister.com/ohio/scioto-county/horseshoe-mound-74001621/"}