Grand Lake is a natural lake, one of the headwaters of the Colorado River in Grand County, Colorado. On its shores is located the eponymous town of Grand Lake. The elevation of the lake surface is 8,367 feet (2,550 meters). It is the largest natural lake in the state of Colorado, formed by the damming of several streams by a glacial moraine. It is adjacent to Rocky Mountain National Park. Grand Lake was named Spirit Lake by the Ute Tribe because they believed the lake's cold waters to be the dwelling place of departed souls and avoided it. Grand Lake forms a continuous body of water with the artificial Shadow Mountain Lake, which then flows into Lake Granby. Water collected in Lake Granby is pumped to Shadow Mountain and Grand Lakes, then under the Continental Divide via the Alva B. Adams Tunnel to the Big Thompson River on the eastern slope of the Rocky Mountains. From here, the water flows into the South Platte River and is used for agriculture, human consumption, and industry. This is the first of many large-scale diversions of water from the Colorado River Basin between Colorado and the Gulf of California.