{"nrhp_refnum":"01000868","name":"United States Post Office-Chicago","other_names":["Old Chicago Main Post Office"],"category":"building","location":{"address":"433 W. Van Buren St.","address_restricted":false,"city":"Chicago","county":"Cook County","state":"IL","lat":41.87609923300005,"lon":-87.63875614799997,"geom_source":"nps_gis"},"listed_date":"2001-08-16","is_nhl":false,"nhl_designated_date":null,"areas_of_significance":["Architecture","Communications","Politics/Government","Transportation","Commerce"],"significance_levels":["national"],"summary":{"what_it_is":"The Old Chicago Main Post Office at 433 West Van Buren Street, Chicago, built in two phases: a 1921 mail distribution building and a much larger 1934 structure that wraps around it, spanning the Eisenhower Expressway and a rail yard beside the Chicago River.","why_significant":"The nomination presents the building as a very large mail processing facility, billed in contemporary materials as the largest post office building in the world. Its 1934 design blends stripped classicism with Art Deco, and its floors housed extensive parcel, letter and administrative operations. The 1921 section also reflects the industrial planning of the Burnham plan.","narrative":"Rising beside the Chicago River just west of the Loop, the Old Chicago Main Post Office occupies two city blocks and bridges both the Eisenhower Expressway and a busy rail yard. It was built in two stages. A 1921 mail distribution building, designed to suit the surrounding industrial area laid out in the Burnham plan, was later enclosed by a far larger 1934 structure, leaving only its east face visible. The 1934 building is clad in limestone, with corner towers, a distinct base, shaft and cap, and a monumental granite stair at the Van Buren Street entrance. Its style combines stripped classicism with streamlined Art Deco. Inside, each floor handled a stage of mail work, from parcel sorting and letter cancellation to a bag depository and administrative offices. The description lists the property as vacant and not in use. It was listed as a single contributing building, notable for its scale, its design and its role in handling the city's mail.","period_of_significance":null,"architect_builder":null,"architectural_style":"Classical Revival/ Art Deco","criteria":[],"status_note":"Current function is listed as vacant, not in use.","vacant_flag":true,"machine_generated":true,"model":"claude-sonnet-5-5","prompt_version":"v1.0-2026-10-29","generated_at":"2026-10-29 02:55:37.360368-05","source_pdf":"https://s3.amazonaws.com/NARAprodstorage/opastorage/live/88/8922/28892288/content/electronic-records/rg-079/NPS_IL/01000868.pdf"},"photo":{"url_800":"https://nationalhistoricalregister.com/media/01000868/d0ee6f7d1a-800.webp","url_1600":"https://nationalhistoricalregister.com/media/01000868/d0ee6f7d1a-1600.webp","licence":"CC BY-SA 3.0","author":"Brianbobcat","credit_html":"<a href=\"https://commons.wikimedia.org/wiki/File:Old_Post_Office.JPG\" rel=\"noopener\">Brianbobcat</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:Old_Post_Office.JPG"},"district":null,"sources":{"nps_snapshot_date":"2026-05-22","nara_catalog":"https://catalog.archives.gov/id/28892288","wikipedia":"https://en.wikipedia.org/wiki/Old_Chicago_Main_Post_Office","wikidata":"https://www.wikidata.org/wiki/Q3881507"},"indexable":true,"url":"https://nationalhistoricalregister.com/illinois/cook-county/united-states-post-office-chicago-01000868/"}