Structure Type: built works - commercial buildings - office buildings; built works - commercial buildings - stores

Designers: Burnham and Root, Architects (firm); Hobart, Lewis P., Architect (firm); Kelham, George William, Architect (firm); Polk, Willis, and Company (firm); Reid Brothers, Architects (firm); Daniel Hudson Burnham (architect); Lewis Parsons Hobart (architect); George William Kelham (architect); Willis Jefferson Polk (architect); James William Reid (architect); Merritt Jonathan Reid (architect); John Wellborn Root (architect)

Dates: constructed 1890-1891

10 stories

view all images ( of 7 shown)

220 Montgomery Street
Financial District, San Francisco, CA 94104-3402

OpenStreetMap (new tab)
Google Map (new tab)
click to view google map
Google Streetview (new tab)
click to view google map
The address was also 220 Bush Street.


D.O. Mills financed this ten-story office building, notable for its adaptation of Chicago School Romanesque styling and its innovative use of a steel frame. John Wellborn Root (1850-1891) has been credited with being the building's designer. According to NoeHill in San Francisco, "The original Mills Building occupied a frontage of 159.5 feet on Montgomery Street and 137.5 feet on Bush. Root was probably the lead designer. His biographer, Harriet Monroe, noted that Root explored four or five different facade treatments. Atmospheric conditions in San Francisco permitted the use of exterior materials such as white marble which would have been impractical in a city such as Chicago." (See NoeHill in San Francisco, "San Francisco Landmark #76," accessed 10/07/2016.)This building was probably one of the last designs by Root before his death, and reflected the influence of the Chicago School architects, Burnham and Root, to change San Francisco's structural systems for high rises from load-bearing masonry to steel frames.

Building History

This large office block, owned by the New York-born banker Darius Ogden Mills (1825-1910), was erected between 1890 and 1892. MIlls was a prime investor in the Bank of California, which, despite a severe setback during 08-09/1875, became one of the state's leading banking institutions. Mills owned extensive real estate holdings in San Francisco and in the area near what is now Millbrae. The San Francisco International Airport site was earlier owned by Mills and his heirs, and the airfield was first called "Mills Field."

The Mills Building stood as the third office tower to contain a steel frame in the city, behind the Chronicle Building (1888-1890), also designed by Burnham and Root, and A. Page Brown's Crocker Building (1890-1891) located at Market Post Streets.

The Swig Company has owned the Mills Building since 1954.

Building Notes

The Mills Building took the spot of Platt's Hall, a significant musical performance space and versatile assembly hall in early San Francisco, built in 1860 and torn down in 1890.

Its Romanesque entry composed of concatenated arches surrounding a fanlight, six fixed lights and a pair of brass and glass doors was its most remarkable decorative detail.

In 1909, the Union Steamship Company, with Donzel Stoney as President, had its offices in the Mills Building. (See San Francisco, California, City Directory, 1909, p. 1568.)


The building was damaged significantly in the San Francisco Earthquake and Fire of 04/18-19/1906. The Architect and Engineer of California said of the damaged building in its issue of 03/1907: "The reconstruction of the Mills Building at the corner of Bush and Montgomery streets, San Francisco, has begun. This is a ten-story structure which it was first supposed would have to be largely removed, but a careful examination discloses the fact that practically all of the steel frame can be used again and that a good portion of the brick walls are in good condition. The building will be fitted up as before as a modern office building." (See "Mills Building," Architect and Engineer of California, vol. VIII, no. 2, 03/1907, p. 90.)

San Francisco architect, Willis J. Polk (1867-1924), supervised the alterations and additions made in 1907 . The Mills Building's stout steel frame withstood the quake's seismic shock, but the ensuing firestorm caused significant damage to its interior. Polk, who worked in Daniel Burnham's architectural office, is thought to have supervised this 02/1907 interior and exterior renovation effort. Polk also designed the full-height, 70-foot extension added along Bush Street in 08/1907.

Additions were also made between 1914 and 1918. First, in 1914, a nearly 69-foot-long, five-story section was made, and four years later, floors 6-10 were added to complete the addition.An engineer, J.S. Bogard, has been credited with supervising the 1914 work.

An adjacent 22-story tower was added to the Mills Building in 1930-1931, designed by San Francisco architects Lewis P. Hobart (1873-1954) and George W. Kelham (1871-1936) to blend with the original Mills Building, stood at 220 Bush Street.

San Francisco Historic Landmark: 76

National Register of Historic Places: 77000334 NRHP Images (pdf) NHRP Registration Form (pdf)

PCAD id: 11455