How to Research a San Francisco Building from the San Francisco Public Library provides excellent guidance and an explanation of resources at SFPL that will assist you.
Local history rooms at the public library near your site, such as the Oakland History Room or the San Francisco History Center.
Local Historical Societies, such as the Berkeley Historical Society and the California Historical Society.
American County Histories in Accessible Archives provides access to many of the thousands of county histories that were published as part of the U.S. Centennial Celebration of 1876. For many counties there is more than one history.