The Mississippi River is perhaps the largest and most complex floodplain river ecosystem in the Northern Hemisphere, and easily the dominant river in North America.  Coursing over 2,300 miles through the heart of the United States, the Mississippi sees vast change from the northern forests of Minnesota to the bayous of the Louisiana delta.

The river changes character more within the 72 miles of the Mississippi National River and Recreation Area than it does anywhere else along its entire length.  It enters the park as a modest-sized river under protection as a state wild and scenic river.  The Mississippi plunges over St. Anthony Falls in Minneapolis, the river's only true waterfall, before coursing through a deep, wooded gorge.  At St. Paul the river opens up into the huge floodplain river made famous by Mark Twain and stays like that all the way to St. Louis, 800 miles downstream.