The term refers to a vast area of grassland owned by the federal government, and often including some privately held land, on which livestock roamed freely. These unfenced expanses were prevalent in the American West, particularly during the 19th century. Cattle, and to a lesser extent sheep, grazed across these territories, supported by the natural forage available. For instance, large cattle ranches in states like Texas and Montana depended on this system to raise and fatten their herds before driving them to market.
This system played a critical role in the economic development of the West. It facilitated the rapid growth of the cattle industry, providing a relatively inexpensive way for ranchers to raise large numbers of animals. The romantic image of the cowboy and the cattle drive are directly linked to this period. However, it also led to conflicts over land and resources, including disputes between cattle ranchers, sheep herders, and farmers, as well as tension with Native American tribes who traditionally used the land for hunting and subsistence.