Kissimmee River, river in central Florida, U.S., flowing between Lakes Kissimmee (north) and Okeechobee (south). It originally had a course of about 100 miles (160 km), but in the 1960s it was canalized for flood-control purposes to a 56-mile (90-km) length. The river basin drains approximately 3,000 square miles (7,700 square km). Efforts were underway shortly after the channel was finished to restore the river to its original state. A portion of the Florida National Scenic Trail roughly parallels the river’s course. The origin of the name Kissimmee is uncertain, but it may be derived from a Calusa Indian word meaning “long water.”