Mills Building, Chicago School skyscraper in the Financial District, San Francisco, United States

The Mills Building is a 10-story, 47 m (154 ft) Chicago School structure with Romanesque design elements in San Francisco's Financial District. Completed in 1892 by Burnham and Root/D.H. Burnham & Company, it was restored by Willis Polk in 1908 after the 1906 earthquake, with additions in 1914 and 1918. Its 22-story, 92 m (302 ft) annex, Mills Tower, was completed in 1932 at 220 Bush Street.

The structure was designed and built in 1892 by the architecture firm Burnham and Root. It survived the 1906 earthquake but required interior reconstruction following the subsequent fire that swept through the city.

The Montgomery Street entrance displays a two-story archway framed by marble Corinthian columns, showcasing architectural traditions that shaped early San Francisco. This formal entryway remains a focal point where visitors recognize the building's classical heritage amid the surrounding urban landscape.

The building houses modern office spaces, conference facilities, tenant lounges, and bike storage for those who need it. Direct access to BART and MUNI transportation is available right from the building, making arrival by public transit straightforward.

The Mills Building is regarded as San Francisco's second skyscraper, after the Chronicle Building of 1890. Its 1932 annex, the 22-story Mills Tower at 220 Bush Street, was designed by George W. Kelham and Lewis Parsons Hobart.