N.P. Dodge Park, Omaha, Nebraska
The Missouri River is one of the Mississippi River's largest tributaries. With its headwaters originating in the mountains of Montana and continuing through its confluence with the Mississippi River just north of Saint Louis, Missouri on down to the Gulf of Mexico, it is the fourth longest river in the world after the Nile River, the Amazon River and the Yangtze River.
See also: Geography of the United States