Hazel Lois McGaa Cuney (1910-1998) was a descendant of two prominent Oglala ranch families from the Manderson and Cuny Table area in the northwest area of Pine Ridge Reservation. As a rancher, federal employee, and historian, she collected and wrote accounts of her family histories and Pine Ridge Reservation histories. Her parents were Mary Lovie Pourier and William Denver McGaa. Her maternal grandparents were Josephine Richard and Jean Baptiste (Big Bat) Pourier. Her paternal grandparents were Jennie Adams and William McGaa. Her only surviving child, Mary Pat Cuney-Farrell (1947-2012), an educator, inherited and maintained her family's extensive collection of Pine Ridge Reservation histories. Hazel McGaa-Cuney grew up on Cuny Table, near the Badlands Bombing Range, on the northwestern portion of reservation boundaries attending school in Scenic and Holy Rosary Mission, finishing high school at St. Agnes Academy in Alliance, Nebraska. Hazel attended secretarial school in Denver and worked various positions within the Bureau of Indian Affairs, later ranching full-time with her mother after retirement.

The manuscript component of the collection contains the written and typed notes of Hazel McGaa Cuney. These include accounts of the Wounded Knee Massacre, the family histories of Cuny Table, and accounts of the effects of the Badlands Bombing Range. There are extensive collections and notes of family histories and genealogies. The ranch business component includes the family ranch business and includes a brand book, ledgers, and related documents. The photograph and slide collection includes copies of photographs from other institutions as well as copies and original prints of family photos spanning several generations. These materials are arranged in series I and IV. Series V was accessioned to the collection in 2016 and processing completed in 2019.