The Mississippi River ranges in depth from 3 feet at its headwaters to 200 feet near New Orleans. The river is dredged to a minimum depth of 9 feet.
According to the National Park Service, the Mississippi River is 2,350 miles long and is the fourth-longest river in the world. It ranges in width from 20 feet to 11 miles. The average surface speed at its headwaters is 1.2 mph and 3 mph near New Orleans. The average flow of the river where it empties into the Gulf of Mexico is 600,000 cubic feet (4.5 million gallons) per second. The Mississippi River watershed is the fourth largest in the world, covering 1.2 million square miles, or 40 percent of the lower 48 states.