{"nrhp_refnum":"77000334","name":"Mills Building and Tower","other_names":[],"category":"building","location":{"address":"220 Montgomery St. and 220 Bush St.","address_restricted":false,"city":"San Francisco","county":"San Francisco","state":"CA","lat":37.791284605000044,"lon":-122.40152331999997,"geom_source":"nps_gis"},"listed_date":"1977-04-13","is_nhl":false,"nhl_designated_date":null,"areas_of_significance":["Architecture"],"significance_levels":["local"],"summary":{"what_it_is":"A steel-frame commercial office building at 220 Montgomery Street and 220 Bush Street in San Francisco, designed in 1890 by the Chicago firm Burnham and Root, with a 22-story tower addition built in 1930-31.","why_significant":"The nomination calls it San Francisco's oldest intact and best surviving example of the Chicago School of architecture, and possibly the city's only link to that era. It is one of the first three steel-frame buildings in the city and remains essentially unchanged from its 1907 reconstruction. It also carries the association of banker D. O. Mills.","narrative":"Located at the corner of Montgomery and Bush Streets in San Francisco, this office building was designed in 1890 by the Chicago firm Burnham and Root, with most of the design credited to John Root. It replaced Platt's Music Hall and was built with a steel frame, white Inyo marble on the lowest two stories, and buff Roman brick and terra cotta above. The 1906 earthquake caused minor exterior damage, and fire badly damaged the interior. Reconstruction began in February 1907 and is attributed to Willis Polk. Additions followed in 1907, 1914 and 1918, and a tower designed by Louis Parsons Hobart was completed in 1930-31, financed largely by proceeds from the sale of Mills Estate land for San Francisco's airport. The building is regarded as the city's oldest intact and finest example of the Chicago School and one of its first three steel-frame structures. It is named for banker D. O. Mills, who founded the first bank west of the Rockies.","period_of_significance":"1890","architect_builder":"Burnham and Root (Chicago); Willis Polk (1907 reconstruction, attributed); J. S. Bogard, Engineer (1918 addition); Louis Parsons Hobart (Mills Tower, 1930-31)","architectural_style":"Chicago School","criteria":[],"status_note":"Listed as occupied, in good condition, in commercial use, and on its original site.","vacant_flag":false,"machine_generated":true,"model":"claude-sonnet-5-5","prompt_version":"v1.0-2026-10-29","generated_at":"2026-10-29 02:55:32.297624-05","source_pdf":"https://s3.amazonaws.com/NARAprodstorage/lz/electronic-records/rg-079/NPS_CA/77000334.pdf"},"photo":{"url_800":"https://nationalhistoricalregister.com/media/77000334/955d9e8fa3-800.webp","url_1600":"https://nationalhistoricalregister.com/media/77000334/955d9e8fa3-1600.webp","licence":"CC BY-SA 3.0","author":"Patrick Nouhailler's…","credit_html":"<a href=\"https://commons.wikimedia.org/wiki/File:San_Francisco-Union_Square-Financial_District_-_panoramio_(51).jpg\" rel=\"noopener\">Patrick Nouhailler's…</a>, <a href=\"https://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:San_Francisco-Union_Square-Financial_District_-_panoramio_(51).jpg"},"district":{"nrhp_refnum":"06000372","name":"Port of San Francisco Embarcadero Historic District","url":"https://nationalhistoricalregister.com/districts/california/port-of-san-francisco-embarcadero-historic-district-06000372/"},"sources":{"nps_snapshot_date":"2026-05-22","nara_catalog":"https://catalog.archives.gov/id/123861210","wikipedia":"https://en.wikipedia.org/wiki/Mills_Building_and_Tower","wikidata":"https://www.wikidata.org/wiki/Q6859956"},"indexable":true,"url":"https://nationalhistoricalregister.com/california/san-francisco/mills-building-and-tower-77000334/"}