Resources for California Newspapers
Several guides and union lists of newspapers are available at university, college, and public libraries. A guide to early California newspapers is J. Budenz, Paul J. Smith, and J.H. Young, comps., Early Newspapers and Periodicals of California and the West (San Francisco, California: W. R. Howell, 1970; Family History Library book 979.4 A3b; film 1421815 item 8).
Libraries and Archives
The California State Library has an extensive collection of California newspapers. Other large libraries in the state also have newspaper collections. Many newspapers are available on microfilm, and some libraries participate in inter-library loan services.
A wiki aticle describing an online collection is found at:
The U.S. Newspaper Directory, 1690-Present is a national directory from the Library of Congress of over 140,000 newspaper titles. The directory provides a list of libraries from around the country that have the newspapers in their collections.
Digital Issues Online
NewspaperArchive.com ($) has a large collection of California newspapers online. This database is sometimes free at libraries under the name AccessNewspaperArchive.
California Digital Newspaper Collection - California Newspaper Project