The main physical features in Denver are, The Rocky Mountains. The Great Plains, Cherry Creek, South Platte, The Colorado Plateau, and The Grand Canyon. The Rocky mountains extend from Wyoming to New Mexico going westward. Pine tree forests surround and cover part of the mountains. The Great Plains cover 40% of Colorado and cover the entire eastern portion of the state. It extends into Nebraska, Kansas, and Oklahoma. Cherry creek was a main source that led to the founding of Denver. South Platte was an important land and area that also lead to the founding of Denver. The Colorado plateau covers the western fifth of the state. The plateau sits at a higher elevation than the Great Plains. Features of this land include tablelands, mesas, dry gullies, deep canyons and shallow basins. The Grand Canyon's oldest beds at the bottom of the Inner Gorge are over 2 billion years old. At its broadest, the Grand Canyon is close to 18 miles across; its greatest depth is 6,000 feet from rim to river.