The Western Sonoma County Historical Society, formed in 1974, is dedicated to the study and appreciation of the history of the West County through educational programs, research, archeological projects, preservation advocacy and the collection and preservation of fine arts, decorative arts, archeological objects, printed and manuscript materials and maps, costumes and weaponry, and historic artifacts related to the heritage of Sebastopol and surrounding towns.
The Western Sonoma County Historical Society's digital collection at California Revealed features oral history recordings and transcripts from the 1960s to the 2010s, as well as meeting notes from the 1900s to the 1940s created by the Sebastopol Grange Lodge No. 306, a farmers' association sponsoring social activities, community service, and political lobbying. The resources provide documentation regarding the history of Western Sonoma County and Northern California, focusing on subjects such as family histories, agriculture, education, and local businesses.