You can find selected issues of
Sonoma County newspapers, which include the Press Democrat
(Santa Rosa), the Argus-Courier (Petaluma) and all
available issues of the Sebastopol Times, Sonoma West
Times and Sonoma West Times & News (Sebastopol,
1895-2016), on the Newspapers.com website
and some older newspapers can be found through California Digital Newspaper
Collection.
Press Democrat (2008 only) and the Geyserville Press are available from Google News. Some Sonoma County-related stories are included in the University of California, Riverside's California Digital Newspaper Collection and the Library of Congress' Chronicling America. The Library has a number of local newspapers on microfilm; holdings for the Press Democrat, Argus-Courier, Cloverdale News and others.
California Digital Newspaper Collection: . . . Search or Search by Newspaper Title
Geyserville Gazette (Geyserville, 1899-1918) . . . Link
Geyserville Press (Geyserville, 1940-1964) . . . Link
Healdsburg Enterprise (Healdsburg, 1878-1929) . . . Link
Healdsburg Tribune (Healdsburg, 1919-1937) . . . Link
Healdsburg Tribune, Enterprise and Scimitar (Healdsburg, 1888-1990) . . . Link
Oak Leaf (Santa Rosa, 1924-2000) . . . Link
Press Democrat (Santa Rosa, 1883-1922) . . . Link
Russian River Flag (Healdsburg, 1865-1886) . . . Link
Sonoma Democrat (Santa Rosa, 1857-1897) . . . Link
Sotoyome Scimitar (Healdsburg, 1902-1944) . . . Link
Google News:
Cloverdale Reveille (1984) . . . Link
The Geyserville Press . . . Link
The Petaluma Argus (1900-1909) . . . Link
Petaluma Daily Argus (1899) . . . Link
Petaluma Journal and Argus (1864-1870) . . . Link
Petaluma Weekly Argus (1875-1878) . . . Link
Newspapers.com Search by City:
Cloverdale Reveille (1880-2004) . . . Link
The Petaluma Argus-Courier (1899-2000) . . . Link
Petaluma Argus (1861-1864) . . . Link or the Morning Edition (1873), Evening Edition (1873), Weekly Edition (1867-1889)
The Petaluma Courier (1876-1896) . . . Link
Petaluma Daily Morning Courier (1891-1928) . . . Link
The Sonoma County Journal (1855-1964) . . . Link
Santa Rosa Press Democrat (1928-1997) . . . Link
Sonoma West Times & News (1895-2016) . . . Link
Cloverdale Reveille . . . Link
The Healdsburg Tribune . . . Link
Regional Newspaper Collection (SSU) . . . Link
Santa Rosa Press Democrat Home Page . .
. Link
Sonoma West Times & News . . . Link
Sonoma County Library Historical
Newspaper Collection Link or
their Microfilm Newspaper Collection
The Sonoma Valley Sun (free to search archives) . . . Link
USGenWeb Sonoma County Archives . . .
Link
Western Sonoma County Historical Society . . . Link
The Windsor Times . . . Link
Biblioteca Vinaria Sonoma .
. . Link
Luther Burbank Home & Garden
Collection
. . . Link
Specific Searches
Earthquake of 1906 Digital Collection . . . Link