Niobrara nīəbrâr´ə [key], river, c.430 mi (690 km) long, rising in the High Plains, E Wyo., and flowing E across N Nebraska to the Missouri River on Nebraska's northeast border. The Mirage Flats irrigation project uses water impounded by Box Butte Dam (completed 1946). A scenic 76-mi (122-km) portion of the river comprises
Niobrara National Scenic River (see National Parks and Monuments, table).
The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2023, Columbia University Press. All rights reserved.
See more Encyclopedia articles on: Compounds and Elements