Clear Creek is a tributary of the South Platte River, approximately 66 miles (106 km) long, in north central Colorado in the United States. The creek flows through Clear Creek Canyon in the Rocky Mountains directly west of Denver, descending through a long gorge to emerge at the town of Golden, finally ending in the Colorado Eastern Plains where it joins the South Platte. Clear Creek is unusual in that it is a stream named "creek" fed by a stream named "river"; typically "rivers" are fed by "creeks", and are larger bodies of water, although the nomenclature is ambiguous and there is no clear system. Fall River empties into Clear Creek along I-70 west of Idaho Springs, Colorado.

The South Platte River is one of the two principal tributaries of the Platte River. Flowing through the U.S. states of Colorado and Nebraska, it is itself a major river of the American Midwest and the American Southwest/Mountain West. Its drainage basin includes much of the eastern flank of the Rocky Mountains in Colorado, much of the populated region known as the Colorado Front Range and Eastern Plains, and a portion of southeastern Wyoming in the vicinity of the city of Cheyenne. It joins the North Platte River in western Nebraska to form the Platte, which then flows across Nebraska to the Missouri. The river serves as the principal source of water for eastern Colorado. In its valley along the foothills in Colorado, it has permitted agriculture in an area of the Colorado Piedmont and Great Plains that is otherwise arid.