{"nrhp_refnum":"76000701","name":"Old Colony Buildings","other_names":[],"category":"building","location":{"address":"407 S. Dearborn St.","address_restricted":false,"city":"Chicago","county":"Cook County","state":"IL","lat":41.969459020000045,"lon":-87.62979388699995,"geom_source":"nps_gis"},"listed_date":"1976-01-02","is_nhl":false,"nhl_designated_date":null,"areas_of_significance":["Community Planning and Development","Engineering","Architecture"],"significance_levels":["state"],"summary":{"what_it_is":"A seventeen-story steel- and iron-framed office building at 407 South Dearborn Street in Chicago's Loop, built in 1893-94 to designs by Holabird & Roche.","why_significant":"The nomination cites the excellence of its design, its status as the only surviving Loop commercial office building with bulging corners, and its innovative structural system. It also contributes to the south Loop district of thin slab buildings from the same era.","narrative":"Completed in 1893-94 at the corner of Dearborn and Van Buren streets in Chicago, this seventeen-story office building was designed by Holabird & Roche and financed by Francis Bartlett of Boston, who supplied its name. A skeletal frame of wrought iron Phoenix columns and steel girders carries the whole structure, with no bearing walls. Portal bracing, apparently invented here, is visible in many offices. Bedford limestone clads the lower three floors, with gray brick and terra cotta above, and rounded oriels give each corner a bulging, sculptural profile. It is the only surviving Loop commercial office building of this slab type with bulging corners; comparable buildings by Burnham and Root and others have been lost. It also anchors the south Loop group of thin slab buildings, and its name inspired Plymouth Court. The facade and cornice remain intact, though the ground floor and lobby have been substantially altered.","period_of_significance":"1893-94","architect_builder":"Holabird & Roche","architectural_style":"Commercial style","criteria":[],"status_note":"Occupied and in commercial use; the facade and cornice remain intact, while the ground floor, lobby and elevators have been altered.","vacant_flag":false,"machine_generated":true,"model":"claude-sonnet-5-5","prompt_version":"v1.0-2026-10-29","generated_at":"2026-10-29 02:55:35.615688-05","source_pdf":"https://s3.amazonaws.com/NARAprodstorage/opastorage/live/92/8923/28892392/content/electronic-records/rg-079/NPS_IL/76000701.pdf"},"photo":{"url_800":"https://nationalhistoricalregister.com/media/76000701/8e9a19bdd3-800.webp","url_1600":"https://nationalhistoricalregister.com/media/76000701/8e9a19bdd3-1600.webp","licence":"CC BY-SA 3.0","author":"User:TonyTheTiger","credit_html":"<a href=\"https://commons.wikimedia.org/wiki/File:20070513_Old_Colony_Building.JPG\" rel=\"noopener\">User:TonyTheTiger</a>, <a href=\"http://creativecommons.org/licenses/by-sa/3.0/\" rel=\"license noopener\">CC BY-SA 3.0</a>, via Wikimedia Commons","source_page":"https://commons.wikimedia.org/wiki/File:20070513_Old_Colony_Building.JPG"},"district":null,"sources":{"nps_snapshot_date":"2026-05-22","nara_catalog":"https://catalog.archives.gov/id/28892392","wikipedia":"https://en.wikipedia.org/wiki/The_Arc_at_Old_Colony","wikidata":"https://www.wikidata.org/wiki/Q14687991"},"indexable":true,"url":"https://nationalhistoricalregister.com/illinois/cook-county/old-colony-buildings-76000701/"}