The collection contains account books and different types of invoices and receipts of businesses operated by three generations of Colgan family members: The Pioneer Hotel, the Colgan Bros. Blacksmithing and Horseshoeing Company, and Colgan's Super Service Station. All businesses were located on the same site at the corner of First and Main Streets in Santa Rosa.

This collection contains selected records of the Dairyman's Coast Bank of Valley Ford, Calif. (earlier called the Dairyman's Bank), including cash and daily balance sheets, savings records and bills receivable.

This collection contains records and related materials from the Sonoma County Superintendent of Schools includes financial documentation pertaining to the operations of the schools within the district, as well as data relating to the geographic division of school boundaries etc. The "Scrapbooks" include newspaper clippings concerning Sonoma County schools for the periods covered.