The Columbia Encyclopedia, Sixth Edition. 2001-07.
Negro, Río, river, Argentina
(r´ n´gr) (KEY) , river, c.400 mi (640 km) long, formed in central Argentina by the confluence of the Neuquén and the Limay rivers, and flowing E across Río Negro prov. (N Patagonia) to the Atlantic Ocean. The river is used for irrigation.