{"nrhp_refnum":"70000236","name":"Monadnock Block","other_names":["Monadock Building"],"category":"building","location":{"address":"53 W. Jackson Blvd.","address_restricted":false,"city":"Chicago","county":"Cook County","state":"IL","lat":41.87804187200004,"lon":-87.62949569399996,"geom_source":"nps_gis"},"listed_date":"1970-11-20","is_nhl":false,"nhl_designated_date":null,"areas_of_significance":["Architecture"],"significance_levels":["national"],"summary":{"what_it_is":"A sixteen-story office building at 53 W. Jackson Blvd. in Chicago, Illinois, begun in 1891 and designed by Burnham and Root, with a southern half added from 1893 by Holabird and Roche.","why_significant":"It is described as the highest and possibly heaviest wall-bearing structure in Chicago and the last skyscraper of solid masonry construction. Its plain, unornamented brick exterior is presented as heralding a new architectural aesthetic and reflecting the Chicago School's drive toward purity of form. It is also tied to John Root, a leading Chicago School designer.","narrative":"Rising sixteen stories and about 215 feet, this Chicago office building at 53 W. Jackson Boulevard was begun in 1891 to designs by Burnham and Root. It was planned as two buildings, the Monadnock and the Kearsarge, each with its own heating plant, elevators, stairs and plumbing so it could be sold separately. In 1893 Holabird and Roche designed the southern half, also conceived as two buildings, and this section includes some vertical steel in its outer walls. The northern portion is notable for walls six feet thick at the base that carry much of the load, making it the highest and possibly heaviest wall-bearing structure in Chicago and said to be the last masonry skyscraper. Its plain brick surface, free of ornament, anticipated a new architectural outlook and reflects the Chicago School's search for refined, pure form. Skidmore, Owings and Merrill remodeled the block in 1938. It was earlier designated a Chicago architectural landmark.","period_of_significance":"19th Century","architect_builder":"Burnham and Root (north half); Holabird and Roche (south half, 1893); Skidmore, Owings and Merrill (1938 remodeling)","architectural_style":"Chicago School","criteria":[],"status_note":"Condition listed as good, unaltered and on its original site; occupied and in commercial use.","vacant_flag":false,"machine_generated":true,"model":"claude-sonnet-5-5","prompt_version":"v1.0-2026-10-29","generated_at":"2026-10-29 02:55:35.128384-05","source_pdf":"https://s3.amazonaws.com/NARAprodstorage/opastorage/live/10/8922/28892210/content/electronic-records/rg-079/NPS_IL/70000236.pdf"},"photo":{"url_800":"https://nationalhistoricalregister.com/media/70000236/c1e6e0eeef-800.webp","url_1600":"https://nationalhistoricalregister.com/media/70000236/c1e6e0eeef-1600.webp","licence":"CC BY-SA 2.5","author":"David K. Staub","credit_html":"<a href=\"https://commons.wikimedia.org/wiki/File:Monadnock.jpg\" rel=\"noopener\">David K. Staub</a>, <a href=\"https://creativecommons.org/licenses/by-sa/2.5\" rel=\"license noopener\">CC BY-SA 2.5</a>, via Wikimedia Commons","source_page":"https://commons.wikimedia.org/wiki/File:Monadnock.jpg"},"district":null,"sources":{"nps_snapshot_date":"2026-05-22","nara_catalog":"https://catalog.archives.gov/id/28892210","wikipedia":"https://en.wikipedia.org/wiki/Monadnock_Building","wikidata":"https://www.wikidata.org/wiki/Q1199833"},"indexable":true,"url":"https://nationalhistoricalregister.com/illinois/cook-county/monadnock-block-70000236/"}