The Mississippi River has the third largest drainage basin in the world, exceeded in size only by the watersheds of the Amazon and Congo Rivers. It drains 41 percent of the 48 contiguous states of the United States. The basin covers more than 1,245,000 square miles, includes all or parts of 31 states and two Canadian provinces. The US Government has tried to improve navigability of the Mississippi River and its major tributaries for more than a hundred years, focused in part by Mississippi River Commission, created in 1879. The river is ever-changing, and in an attempt to understand their domain, and in 1941, MCR hired Harold Norman Fisk to conduct a geological investigation of the Lower Mississippi Valley. The result was a colorful map that displayed the historical course of the riverway from southern Illinois to southern Louisana. His vivid maps are available online in full, but beware: the files are very large.