{"nrhp_refnum":"70000511","name":"Miamisburg Mound","other_names":["Miamisburg Mound State Memorial"],"category":"site","location":{"address":"SE of Miamisburg on OH 725","address_restricted":false,"city":"Miamisburg","county":"Montgomery County","state":"OH","lat":39.62738916300003,"lon":-84.28085250099997,"geom_source":"nps_gis"},"listed_date":"1970-11-10","is_nhl":false,"nhl_designated_date":null,"areas_of_significance":["Prehistoric"],"significance_levels":["state"],"summary":{"what_it_is":"A large prehistoric earthen burial mound on a 100-foot bluff about one mile southeast of Miamisburg, in Miami Township, Montgomery County, Ohio, built by the Adena culture and now part of a state memorial.","why_significant":"The nomination calls it the largest prehistoric burial mound in Ohio and reputedly in the eastern United States. It was built by the Adena people, probably in late Adena times, and has been a noted landmark since American settlers arrived in the Great Miami River Valley. It has never been fully explored scientifically.","narrative":"Rising from a 100-foot bluff southeast of Miamisburg, this earthwork measures 877 feet around its base and about 70 feet high, with some writers reporting 85 feet. Its base covers roughly an acre and a half, and 116 steps lead to the summit. Adena people built it, probably in late Adena times and likely in stages over a long period, which would have required a large and stable settled community. It is described as the largest prehistoric burial mound in Ohio and reputedly in the eastern United States. In 1869 local citizens sank a shaft and found a single skeleton near the top and flat stones at 24 feet that resembled an altar. No complete scientific exploration has been done. Charles Kettering bought the mound in 1920 and gave it to the Ohio Historical Society in 1929, and additional land was donated in 1936. Trees and ground cover have covered it since the early 1800s. The nominated area was reduced to the mound alone, about 1.5 acres.","period_of_significance":"Pre-Columbian (Adena, 500 B.C.-400 A.D.)","architect_builder":"Adena Indians (prehistoric)","architectural_style":null,"criteria":[],"status_note":"Condition rated excellent and altered; the site is public, unoccupied and unrestricted, used as a park. Excavation scars were erased, steps and fences added, and the mound landscaped.","vacant_flag":null,"machine_generated":true,"model":"claude-sonnet-5-5","prompt_version":"v1.0-2026-10-29","generated_at":"2026-10-29 02:53:09.944576-05","source_pdf":"https://s3.amazonaws.com/NARAprodstorage/lz/electronic-records/rg-079/NPS_OH/70000511.pdf"},"photo":null,"district":null,"sources":{"nps_snapshot_date":"2026-05-22","nara_catalog":"https://catalog.archives.gov/id/71990366","wikipedia":null,"wikidata":null},"indexable":true,"url":"https://nationalhistoricalregister.com/ohio/montgomery-county/miamisburg-mound-70000511/"}