The Rosebud Valley was home to nomadic hunter-gatherer groups many centuries ago, with the first accounts coming from the oral traditions of historic tribal groups. Ancestors of the tribes that inhabit the Northern Plains today came there to hunt bison, deer, elk, pronghorn, and bear, which provided food, clothing, shelter, utensils, and ornamentation. Although designated as Montana Territory at the time of the Rosebud Battle, the Sioux, Northern Cheyenne, Crow, and Arapahoe considered this place their free and open homeland. Following the Rosebud Battle and confinement of tribal groups to reservations, this part of Montana began to fill with homesteaders who fenced and farmed the land. The first homesteader on the battleground field, August Ahrens, arrived in 1898. Since then, cattle ranching has dominated land use. Elmer "Slim" Kobold, who arrived in 1911, was the last private landowner; he assisted in placing battlefield monuments and conducted amateur excavations, and he worked to ensure lasting protection for the battlefield. In 1972, a portion of the battlefield was listed in the National Register of Historic Places. The probability of coal mining in the immediate vicinity prompted Kobold to sell the property to the State of Montana in 1978, to be designated as a state park. The 3,052-acre park does not encompass the entire battlefield.