- Osage River
River, western Missouri, U.S. Formed by the junction of the Marais des Cygnes and Little Osage rivers, it is about 500 mi (800 km) long and is the largest tributary of the Missouri River.It flows east and northeast through Lake of the Ozarks and enters the Missouri just east of Jefferson City, Mo.
* * *river rising as the Marais des Cygnes (French: “Swan Marshes”) in the Flint Hills near Eskridge, Kan., U.S. It becomes the Osage (named for the Osage Indians) after its junction with the Little Osage near Rich Hill, Mo., and then flows east through the Ozark highlands to enter the Missouri River near Jefferson City. The river is 500 miles (800 km) long and drains 15,300 square miles (39,600 square km). Along the middle of its course the Osage River is dammed by Bagnell Dam, which thereby impounds the Lake of the Ozarks (Ozarks, Lake of the) (q.v.). The dam was built in 1931 to produce electricity for St. Louis.
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