The Buffalo Commons is a conceptual proposal to create a vast nature preserve by returning 139,000 square miles (360,000 km2) of the drier portion of the Great Plains to native prairie, and by reintroducing the American bison ("buffalo"), that once grazed the shortgrass prairie. The proposal would affect ten states: Montana, Wyoming, Colorado, Oklahoma, New Mexico, Texas, North Dakota, South Dakota, Nebraska, and Kansas.

The American bison, also called the American buffalo or simply buffalo, is a species of bison native to North America. It is one of two extant species of bison, alongside the European bison. Its historical range circa 9000 BC is described as the great bison belt, a tract of rich grassland from Alaska to the Gulf of Mexico, east to the Atlantic Seaboard, as far north as New York, south to Georgia, and according to some sources, further south to northern Florida, with sightings in North Carolina near Buffalo Ford on the Catawba River as late as 1750.