{"nrhp_refnum":"76000697","name":"Manhattan Building","other_names":[],"category":"building","location":{"address":"431 S. Dearborn St.","address_restricted":false,"city":"Chicago","county":"Cook County","state":"IL","lat":41.88493504200005,"lon":-87.62896088299999,"geom_source":"nps_gis"},"listed_date":"1976-03-16","is_nhl":false,"nhl_designated_date":null,"areas_of_significance":["Community Planning and Development","Engineering","Architecture"],"significance_levels":["national"],"summary":{"what_it_is":"A sixteen-story commercial office building at 431 South Dearborn Street in Chicago's Loop, built in 1889-90 and designed by William LeBaron Jenney. It sits mid-block between older buildings, with finished facades on Dearborn Street and Plymouth Court.","why_significant":"It is the oldest surviving office building by Jenney, who helped bring skeletal skyscraper construction to maturity. It is an excellent early skyscraper and a place where key technical advances in skeletal framing were perfected. It is also a key element of the south Loop thin slab district.","narrative":"Rising sixteen stories on South Dearborn Street in Chicago, this office building of 1889-90 was designed by William LeBaron Jenney and was the first to reach that height. Its walls carry no load; a frame of cast iron, wrought iron and early Bessemer steel supports everything. Jenney, with engineer Louis E. Ritter, worked out several techniques that later skyscrapers relied on: cantilevered outer walls that spared the footings of neighboring buildings, hangers that tie masonry to the frame, and early wind bracing. The facade combines cast iron panels, granite, pressed brick and terra cotta, with tiers of rounded and polygonal oriels and a setback above the ninth floor. It is the oldest surviving Jenney office building and a key part of the south Loop thin slab district. The facades remain largely intact, though the original Dearborn entrance has been covered and the interiors have been heavily altered.","period_of_significance":"1889-90","architect_builder":"William LeBaron Jenney","architectural_style":null,"criteria":[],"status_note":"Occupied; facades remain virtually intact, but interior alterations are extensive and many of the first ten floors connect to the neighboring Plymouth building.","vacant_flag":false,"machine_generated":true,"model":"claude-sonnet-5-5","prompt_version":"v1.0-2026-10-29","generated_at":"2026-10-29 02:55:35.513104-05","source_pdf":"https://s3.amazonaws.com/NARAprodstorage/opastorage/live/90/8923/28892390/content/electronic-records/rg-079/NPS_IL/76000697.pdf"},"photo":{"url_800":"https://nationalhistoricalregister.com/media/76000697/62b368fd6d-800.webp","url_1600":"https://nationalhistoricalregister.com/media/76000697/62b368fd6d-1600.webp","licence":"CC BY 2.0","author":"Marlin Keesler from Streamwood, IL","credit_html":"<a href=\"https://commons.wikimedia.org/wiki/File:Manhattan_building_(32872192497).jpg\" rel=\"noopener\">Marlin Keesler from Streamwood, IL</a>, <a href=\"https://creativecommons.org/licenses/by/2.0\" rel=\"license noopener\">CC BY 2.0</a>, via Wikimedia Commons","source_page":"https://commons.wikimedia.org/wiki/File:Manhattan_building_(32872192497).jpg"},"district":null,"sources":{"nps_snapshot_date":"2026-05-22","nara_catalog":"https://catalog.archives.gov/id/28892390","wikipedia":"https://en.wikipedia.org/wiki/Manhattan_Building_(Chicago)","wikidata":"https://www.wikidata.org/wiki/Q3285816"},"indexable":true,"url":"https://nationalhistoricalregister.com/illinois/cook-county/manhattan-building-76000697/"}