The Sandstone Ranch Collection is comprised of bank statements, letters, correspondence, and photographs relating to the Wilson family from 1907 to 1941. The collection includes information about the financial aspect of the Wilson Ranch, later renamed the Sandstone Ranch, located outside of Las Vegas, Nevada. The collection also includes information about the personal lives of those working on the including contracts about grazing cattle, selling cattle, and appropriation of water.

The Six Companies, Inc. Hoover Dam Photograph Collection (1931-1935), consists of approximately 400 black-and-white photographic prints contained in two photograph albums and an additional twenty-one loose black-and-white photographic prints with ten corresponding photographic negatives.