North Fork American River
The North Fork American River is the longest branch of the American River in Northern California. It is long from its source at the crest of the Sierra Nevada, near Lake Tahoe, to its mouth at Folsom Lake northeast of Sacramento. Prior to the construction of Folsom Dam the river was about longer making for a total length of .
Tributary
In the United States, where tributaries sometimes have the same name as the river into which they feed, they are called forks. These are typically designated by compass direction. For example, the American River receives flow from its North, Middle, and South forks. The Chicago River's North Branch has the East, West, and Middle Fork; the South Branch has its South Fork, and used to have a West Fork as well (now filled in).