Just north of St. Louis, three major rivers of North America come together. The Mississippi and Missouri are famous; the Illinois River does not get the attention it deserves. Taken together, these three rivers formed part of a 19^th century strategy to connect the mid-continent to global trade.

All three rivers were heavily traveled in the years prior to steam or diesel-powered riverboats. As powered riverboats became more important tools of commerce, all three rivers needed modifications in order to support the demands of commercial navigation. Below the area shown in this map, the Mississippi is generally large enough to allow commercial navigation with the help of dredging and removal of snags and obstructions. Above here, however, the Mississippi needed to be divided into a chain of lakes, impounded behind dams, with locks to allow vessels to pass. Navigation on the Missouri was supported with a system of engineered obstructions that narrowed and deepened the channel.

The Illinois River was, perhaps, the most dramatically modified of the three. At Chicago, a channel was built that allowed water from Lake Michigan to flow into the upper Illinois River. This additional water supported navigation and also allowed the city of Chicago to flush its sewage into the Illinois River rather than into Lake Michigan, from which it drew drinking water. The opening of the Illinois to navigation brought a promise of connecting the American Midwest to a seamless network of global water transport, taking advantage of the newly-built Panama Canal, so that cites like St. Louis and Chicago could become international seaports, a vision that never came to complete fruition.