{"nrhp_refnum":"85002840","name":"Gage Group-Ascher, Keith, and Gage Buildings","other_names":[],"category":"building","location":{"address":"18--30 S. Michigan Ave.","address_restricted":false,"city":"Chicago","county":"Cook County","state":"IL","lat":41.88124290600007,"lon":-87.63699965599994,"geom_source":"nps_gis"},"listed_date":"1985-11-14","is_nhl":false,"nhl_designated_date":null,"areas_of_significance":["Architecture"],"significance_levels":["state"],"summary":{"what_it_is":"A group of three connected commercial buildings at 18, 24 and 30 South Michigan Avenue in Chicago, facing Grant Park, built in 1898-1899 on a common foundation and steel frame.","why_significant":"The nomination argues the group shows two contrasting approaches of the Chicago school of commercial architecture on one shared structure. Holabird & Roche designed the plain, grid-like facades at 24 and 30 South, while Louis Sullivan designed the richly ornamented terra cotta facade at 18 South. Scholars cited in the form praise both designs as outstanding examples.","narrative":"Three adjoining commercial buildings at 18, 24 and 30 South Michigan Avenue in Chicago face Grant Park. Although they look like separate buildings, they were built in 1898-1899 as one structure with a shared foundation and steel frame. Holabird & Roche designed the structure and the two southern sections, which are faced in red brick and terra cotta with uniform grids of Chicago windows. Louis Sullivan designed the northern section at 18 South, clad in cream-colored terra cotta with botanical capitals, medallions and geometric ornament. The form argues that setting a plain, logical treatment beside a richly ornamented one makes the group an unusually clear statement of the Chicago school of commercial architecture. Later changes include added stories, removed cornices, replaced windows and altered ground floors. Writers such as Carl Condit and Thomas Tallmadge praised the designs, and the group was recognized as nationally significant for its architecture.","period_of_significance":"1898-1899","architect_builder":"Holabird & Roche, Louis H. Sullivan","architectural_style":"Chicago style commercial building (Chicago school)","criteria":[],"status_note":"Listed as occupied and in commercial use; altered over time, with added stories, removed cornices and replaced ground floors.","vacant_flag":false,"machine_generated":true,"model":"claude-sonnet-5-5","prompt_version":"v1.0-2026-10-29","generated_at":"2026-10-29 02:55:35.787704-05","source_pdf":"https://s3.amazonaws.com/NARAprodstorage/opastorage/live/49/8919/28891949/content/electronic-records/rg-079/NPS_IL/85002840.pdf"},"photo":{"url_800":"https://nationalhistoricalregister.com/media/85002840/9aa62f4770-800.webp","url_1600":"https://nationalhistoricalregister.com/media/85002840/9aa62f4770-1600.webp","licence":"Public domain","author":null,"credit_html":"<a href=\"https://commons.wikimedia.org/wiki/File:Gage_Buildings_-_Chicago,_Illinois.jpg\" rel=\"noopener\">Unknown author</a>, Public domain, via Wikimedia Commons","source_page":"https://commons.wikimedia.org/wiki/File:Gage_Buildings_-_Chicago,_Illinois.jpg"},"district":{"nrhp_refnum":"12001238","name":"West Loop-LaSalle Street Historic District","url":"https://nationalhistoricalregister.com/districts/illinois/west-loop-lasalle-street-historic-district-12001238/"},"sources":{"nps_snapshot_date":"2026-05-22","nara_catalog":"https://catalog.archives.gov/id/28891949","wikipedia":"https://en.wikipedia.org/wiki/Gage_Group_Buildings","wikidata":"https://www.wikidata.org/wiki/Q3094314"},"indexable":true,"url":"https://nationalhistoricalregister.com/illinois/cook-county/gage-group-ascher-keith-and-gage-buildings-85002840/"}