Most of Jackson County is a high relatively broad intermontane basin known as North Park, which covers . This basin opens north into Wyoming and is rimmed on the west by the Park Range and Sierra Madre Range, on the south by the Rabbit Ears Range and the Never Summer Mountains, and on the east by the Medicine Bow Mountains. Elevations range from 7,800 to above sea level and is home to the head waters of the North Platte River. The term park is derived from parc, the French word for game preserve. At one time North Park was filled with herds of deer, antelope and buffalo. There were so many buffalo in the area the Ute Tribe gave North Park the name Bull Pen. Now deer, elk, and cattle vie for the same area.