Both forks rise along the eastern flank of the Mosquito Range, on the western side of South Park, which is drained by the tributaries at the headwaters of the river.

At Littleton, the river is impounded to form Chatfield Reservoir, a flood-control basin for the Denver metropolitan area.

The valley through Denver is highly industrialized, serving generally as the route for both the railroad lines, as well as Interstate 25.

On the north side of Denver, it is joined somewhat inconspicuously by Clear Creek, which descends from the mountains to the west in a canyon that was the cradle of the Pike's Peak Gold Rush.

North of Denver, it flows through the agricultural heartland of the Piedmont (a shale region that was formed through erosion by the ancestor of the river following the creation of the Rockies).

By 1910 the increase in agriculture caused the river to reach the border of Colorado and Wyoming due to return flows and dams holding back water later in the year.

Increasing diversions from the upper Colorado River in the 20th century mean that flows reach the North Platte year round.

[4] The South Platte was originally called Niinéniiniicíihéhe by the native Arapaho people who lived on its banks.

Long before the city of Denver was created, many travelers came to the South Platte River to escape the arid Great Plains.

Cheesman was the first reservoir of Denver's mountain storage facilities, and has been designated a National Historic Civil Engineering Landmark.

Below Strontia Springs, the South Platte runs through Waterton Canyon before entering Chatfield Reservoir.

[9] As a result of its close proximity to Denver, the river has thousands of fly fishing enthusiasts visit each year.