Grand Teton National Park is a United States National Park located in western Wyoming, south of Yellowstone National Park. It is named after Grand Teton, which at 13,770 feet, is the tallest mountain in the Teton Range. Part of the Rocky Mountains, the north-south-trending Teton Range rises from the floor of Jackson Hole without any foothills along a 40 mile long by 7 to 9 miles wide active fault-block mountain front system.