U.S. rivers scaled according to their flow volume… Here are the ten largest U.S. rivers ranked by average discharge: •Mississippi River: ~593,000 cubic feet per second •St. Lawrence River (shared with Canada): ~348,000 cfs •Ohio River: ~281,000 cfs •Columbia River: ~265,000 cfs •Sacramento River: ~90,000 cfs •Missouri River: ~86,000 cfs •Tennessee River: ~70,000 cfs •Arkansas River: ~41,000 cfs •Colorado River: ~22,000 cfs (heavily diverted) •Hudson River: ~21,000 cfs These figures represent rough long-term averages. Actual flow can vary widely, and dams or water diversions—especially in western rivers like the Colorado and Arkansas—can significantly reduce discharge.(Historic Vids)