<P> The Missouri River is a long stream that originates in southwest Montana and flows southeasterly for 2,522 miles; passing through six states before finally entering the Mississippi River at St. Louis . The Missouri River is the longest river on the North American continent . The Missouri River was one of the main routes for the watershed expansion of the United States during the 19th century . </P> <P> The Ohio River runs 981 miles (1582 km) long, starting at the meeting of the Allegheny River and the Monongahela River in Pittsburgh, Pennsylvania; ending in Cairo, Illinois, where it then flows into the Mississippi . The Ohio River flows through six states, including, Illinois, Indiana, Ohio, Kentucky, Pennsylvania and West Virginia . </P> <P> The river is a location with the capacity to provide enough water for over five million people . At its widest point, it is one mile wide at Smithland dam. The average depth is 24 feet deep which allows multiple species of fish to live there safely . </P> <P> The water is also home to 150 species of fish ranging from catfish to certain species of salmon and trout . The depth also allows for commerce throughout the river on barges . On average the Ohio River transports over 230 million tons of cargo . Typically, the cargo being shipped are energy resources such as coal . These resources account for 70% of the cargo . Along with shipping energy resources, the Ohio River also creates energy with dams and other power generating facilities . There are 20 dams and 49 other power generating facilities on the Ohio River . </P>

What are the three tributaries of the mississippi river