{"nrhp_refnum":"100010579","name":"Johnstown Flood National Memorial","other_names":[],"category":"district","location":{"address":"733 Lake Road","address_restricted":false,"city":"Adams","county":"Cambria County","state":"PA","lat":40.34328100000005,"lon":-78.7760687111896,"geom_source":"nps_gis"},"listed_date":"2024-07-26","is_nhl":false,"nhl_designated_date":null,"areas_of_significance":["Social History"],"significance_levels":["national"],"summary":{"what_it_is":"The Johnstown Flood National Memorial is a 163-acre park in Croyle and Adams Townships, Cambria County, Pennsylvania, containing the remnants of the South Fork Dam, built in the 1840s and 1850s, and the Elias J. Unger House and farm buildings. The dam was built by the Commonwealth of Pennsylvania between 1838 and 1853.","why_significant":"The nomination argues that the 1889 failure of the South Fork Dam caused the most notable and devastating flood of the nineteenth century in the United States and the greatest national catastrophe of the post-Civil War era. The dam itself is significant as a canal water-supply reservoir and recreational lake, and the Unger House is linked to the events of the flood through Elias J. Unger's role at the site.","narrative":"Remnants of the South Fork Dam lie in a wooded valley in Cambria County, Pennsylvania. The Commonwealth of Pennsylvania built the earthen and rock-fill dam between 1838 and 1853 to supply water to the Western Division of the Pennsylvania Main Line Canal between Johnstown and Pittsburgh. The Pennsylvania Railroad left the dam largely unattended after 1857, and in 1879 a group of Pittsburgh industrialists formed the South Fork Fishing and Hunting Club, which bought the dam and reservoir and repaired it by 1881. On May 31, 1889, after heavy rains, the poorly reconstructed dam failed, releasing a wall of water that killed more than 2,200 people and caused over $17 million in property damage. The surviving abutments, spillway and sluice foundations show how the dam was built and operated. The Elias J. Unger House, constructed in the mid-1880s, is linked to the disaster because Unger, the club's president, was at the site and tried to lower the water level before the collapse.","period_of_significance":"1838-1889","architect_builder":"Commonwealth of Pennsylvania; South Fork Hunting and Fishing Club of Pittsburgh (reconstruction in early 1880)","architectural_style":"Vernacular Gothic Revival (Unger House)","criteria":["A","B","C","D"],"status_note":"The South Fork Dam is reduced to its north and south abutments, spillway and foundation remnants; the Unger House was unoccupied for about ten years before 1981, is stabilized with a temporary roof, and the spring house and barns are collapsed or in poor condition.","vacant_flag":true,"machine_generated":true,"model":"claude-haiku-5-5","prompt_version":"v1.1-2026-10-29","generated_at":"2026-10-29 17:10:27.517728-05","source_pdf":"https://s3.amazonaws.com/NARAprodstorage/lz/electronic-records/rg-079/NPS_PA/66000656.pdf"},"photo":null,"district":null,"sources":{"nps_snapshot_date":"2026-05-22","nara_catalog":null,"wikipedia":null,"wikidata":null},"indexable":true,"url":"https://nationalhistoricalregister.com/pennsylvania/cambria-county/johnstown-flood-national-memorial-100010579/"}