Gunnison, river, 180 mi (290 km) long, rising in W central Colo. and flowing SW, W, and NW to the Colorado River at Grand Junction. It flows through magnificent canyons, notably the Black Canyon of the Gunnison, a national park. Gunnison Tunnel, c.5 mi (8 km) long, was built between 1905 and 1909 to divert the river's water to the Uncompahgre Valley for irrigation.
The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2012, Columbia University Press. All rights reserved.