Early 19th century explorers called the immense expanse of North American grasslands 'The Great American Desert' and declared it unfit for settlement. Yet, it furnished abundant grazing for vast herds of bison, elk, deer and antelope. From the forests on the North Saskatchewan River south into Texas and from the forested foothills of the Rocky Mountains to the woodlands south of the Great Lakes, the Great Plains stretches across a million square miles, rolling toward distant horizons in all directions.