The Harmon Family Papers consist of the political and personal correspondence of Las Vegas, Nevada pioneer Harley A. Harmon from 1910 to 1934, and his son, Harley E. Harmon, from 1950 to 1966. The collection also includes correspondence, personal papers, and photographs of Harley L. Harmon from approximately 1950 to 1999. Also included are family scrapbooks with wedding announcements, photographs, birthday cards, newspaper clippings, and other ephemera.

The Marie and James B. McMillan Photograph Collection (1900-1994) contains photographs of Marie and James B. McMillan and their families. The collection also includes photographs of their friends and professional associates, including journalist Hank Greenspun, Nevada civil rights pioneer J. David Hoggard, and entertainer Sammy Davis Jr. Marie McMillan is a former Las Vegas, Nevada flight instructor and one of the first women to work at the Nevada Test Site in Nye County, Nevada. James B. McMillan was the first African-American dentist to practice in Nevada, as well as a prominent Nevada civil rights leader.

The Helen J. Stewart Photographs depict the Stewart Family from approximately 1860 to 1950. The photographs primarily depict Helen J. Stewart and her children as well as the Stewart Ranch (also know as the Las Vegas Ranch) in Southern Nevada. The photographs include the early Las Vegas, Nevada town site, landscapes of Southern Nevada and the American Southwest, mines and mining camps, railroads and railroad workers, the Las Vegas Fort (also known as the Old Mormon Fort), hotels and early businesses in Las Vegas, Native Americans and Native American artifacts, and postcards.