{"nrhp_refnum":"75001418","name":"Ingalls Building","other_names":["The Transit Building"],"category":"building","location":{"address":"6 E. 4th St.","address_restricted":false,"city":"Cincinnati","county":"Hamilton County","state":"OH","lat":39.095328737000045,"lon":-84.50674687499998,"geom_source":"nps_gis"},"listed_date":"1975-03-07","is_nhl":false,"nhl_designated_date":null,"areas_of_significance":["Engineering","Architecture"],"significance_levels":["state"],"summary":{"what_it_is":"A sixteen-story reinforced-concrete office building at 6 East Fourth Street in Cincinnati, Hamilton County, Ohio, also known as the Transit Building, constructed in 1902-03.","why_significant":"The nomination presents it as a pioneer work of reinforced-concrete construction and believes it to be the world's first concrete skyscraper. It combined all the major reinforced-concrete techniques then developed, and its construction offered lessons for later methods of building large urban structures. It was recognized in 1974 as a National Historic Civil Engineering Landmark.","narrative":"Rising sixteen stories and 210 feet on a 50 by 100 foot footprint at 6 East Fourth Street, this Cincinnati office building was completed in 1902-03 with a frame made entirely of reinforced concrete. Its first three stories are faced in Vermont marble, and the floors above are covered in gray enameled brick. The design follows the late classical revival, with giant pilasters, an ornate entrance architrave and a heavy bracketed cornice. Elzner and Anderson were the architects, Henry Hooper was the structural engineer and the William H. Ellis Co. was the general contractor. The building is believed to be the world's first concrete skyscraper. Concrete was chosen mainly for economy, at a structural cost of $400,000, somewhat below steel. It also spared the site the heavy traffic and hoisting equipment that steel framing required. Critics predicted collapse, yet it remains in excellent condition, and the American Society of Civil Engineers named it a National Historic Civil Engineering Landmark in 1974.","period_of_significance":"1902-03","architect_builder":"Architects Elzner and Anderson; structural engineer Henry Hooper; general contractor William H. Ellis Co.","architectural_style":"Late classical revival","criteria":[],"status_note":"Listed as occupied, in excellent condition and unaltered; the statement says it survives in active use.","vacant_flag":false,"machine_generated":true,"model":"claude-sonnet-5-5","prompt_version":"v1.0-2026-10-29","generated_at":"2026-10-29 02:53:09.152504-05","source_pdf":"https://s3.amazonaws.com/NARAprodstorage/lz/electronic-records/rg-079/NPS_OH/75001418.pdf"},"photo":{"url_800":"https://nationalhistoricalregister.com/media/75001418/68d4ffa470-800.webp","url_1600":"https://nationalhistoricalregister.com/media/75001418/68d4ffa470-1600.webp","licence":"CC BY-SA 4.0","author":"Hhelvey","credit_html":"<a href=\"https://commons.wikimedia.org/wiki/File:Ingalls_Building,_Cincinnati.jpg\" rel=\"noopener\">Hhelvey</a>, <a href=\"https://creativecommons.org/licenses/by-sa/4.0\" rel=\"license noopener\">CC BY-SA 4.0</a>, via Wikimedia Commons","source_page":"https://commons.wikimedia.org/wiki/File:Ingalls_Building,_Cincinnati.jpg"},"district":null,"sources":{"nps_snapshot_date":"2026-05-22","nara_catalog":"https://catalog.archives.gov/id/71989083","wikipedia":"https://en.wikipedia.org/wiki/Ingalls_Building","wikidata":"https://www.wikidata.org/wiki/Q14690693"},"indexable":true,"url":"https://nationalhistoricalregister.com/ohio/hamilton-county/ingalls-building-75001418/"}