How can the river flow upwards against the curvature of the Earth during half of its path? The Mississippi River begins at Lake Itasca, a small glacial lake in northern Minnesota, and flows southward for about 2,350 miles (3,782 km) until it reaches the Gulf of Mexico.Mar 10, 2017 https://www.livescience.com › 5822... Mississippi River: North America's Mighty River | Live Science