(Encyclopedia) Ohio, river, 981 mi (1,579 km) long, formed by the confluence of the Allegheny and Monongahela rivers in SW Pa., at Pittsburgh; it flows northwest, then generally southwest to enter…
(Encyclopedia) Oka, river, c.600 mi (970 km) long, rising in the Sayan Mts., Buryat Republic, S central Siberian Russia. It flows N through Irkutsk oblast to join the Angara River below Bratsk. The…
(Encyclopedia) Negro, RíoNegro, Ríorēˈō nāˈgrō [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…
(Encyclopedia) Madison, river, 183 mi (295 km) long, rising in Yellowstone National Park, NW Wyo., and flowing W then N through SW Montana to join the Jefferson and Gallatin rivers at the Three Forks…
(Encyclopedia) Kentucky, river, 259 mi (417 km) long, formed by the junction of the North Fork and the Middle Fork rivers, central Ky., and flowing NW to the Ohio River at Carrollton. Frankfort, Ky…
(Encyclopedia) Minnesota, river, 332 mi (534 km) long, rising in Big Stone Lake at the W boundary of Minnesota and flowing SE to Mankato, then NE to the Mississippi S of Minneapolis. Earlier called…
(Encyclopedia) Mississippi, river, principal river of the United States, c.2,350 mi (3,780 km) long, exceeded in length only by the Missouri, the chief of its numerous tributaries. The combined…
(Encyclopedia) Missouri, river, c.2,565 mi (4,130 km) long (including its Jefferson-Beaverhead-Red Rock headstream), the longest river of the United States and the principal tributary of the…
(Encyclopedia) Missouri River basin project, comprehensive plan authorized in 1944 for the coordinated development of water resources of the Missouri River and its tributaries, draining an area of c.…
(Encyclopedia) Menominee, river, 118 mi (190 km) long, formed by the union of the Brule and the Michigamme rivers above Iron Mountain, W Upper Peninsula, N Mich., and flowing SE into Green Bay at…
