The valley is formed by the Teton Range to the west and the Gros Ventre Range to the east. Grand Teton National Park occupies the northwestern part of the valley, encompassing much of the Teton Range and Jackson Lake. The city of Jackson is at the southern end. Between them lies, on U.S. Route 26, Glacier View Turnout offering a view of Teton Glacier on the north of Grand Teton, and the National Elk Refuge, home of the largest elk herd on earth. The Snake River threads through the entire valley from its headwater in Yellowstone in the north to the mouth of the Snake River Canyon at the southern tip of the valley. Blacktail Butte is a prominent landform rising from the valley floor. The average elevation of the valley is over above sea level.