River, Colorado, Wyoming, and Nebraska, U.S. One of the two main arms of the Platte River , it rises in northern Colorado, flows north into Wyoming, then turns east and southeast across the Nebraska border to join the South Platte and form the Platte.
It is 680 mi (1,094 km) long and is part of an irrigation, power, and flood-control project of the Missouri River basin. It has large reservoirs and dams.