Elk Ranch flats is the park's last operating irrigated cattle and hay ranch. In the early 1900s, David (Si) Ferrin consolidated several homesteads to establish one of the valley's largest cattle ranches. After an agricultural depression in the 1920s, Ferrin sold his land to the Snake River Land Company. These lands became part of the park in 1950. Today, livestock, bison, elk and pronghorn graze in the fields and a few cabins remain.
Elk Ranch was a large cattle ranch back in the early 1900s. The ranch headquarters were homesteaded by Otto Kusche in 1911. After changing ownership several times, the ranch was purchased by J.D. "Si" Ferrin in 1920. The agricultural depression of the late 1920s forced many ranchers including Ferrin to sell out to the Snake River Land, Co.