On land inhabited by the Coast Miwok as many as 12,000 years ago, Mill Valley spawned from a Mexican government land grant to set up Rancho Corte Madera del Presidio on a wide swath of Southern Marin. The grant was issued in 1834 to John Thomas Reed, who built the town's namesake sawmill in Old Mill Park to provide lumber for the new military post being built in the Presidio in San Francisco.
The town was incorporated in September 1900, and the first Town Hall was constructed seven years later. By 1910, the town's population was 2,500 and has only grown to 13,200, as of 2008. The current City Hall was built in 1937. Public buildings and facilities opened throughout the decades, but City Hall remained the hub for local government.
While the Public Safety Building, constructed in the 1970s, is home to the city's police and fire departments, most city agencies are housed at City Hall. City Manager Jim McCann coordinates all city departments through eight department directors, Police Chief, Fire Chief, Director of Planning and Building, Public Works Director, Finance and Human Resources Director, Parks and Recreation Director, City Librarian, and the General Manager of the Wastewater Treatment Plant.