The undependable state of the Upper Mississippi and Illinois rivers grabbed the attention of the United States Congress who in turn commissioned the U.S. Army Corps of Engineers to develop a system whereby commercial traffic could navigate the Upper Mississippi River and Illinois Waterway unencumbered by the characteristic hazards of the rivers.

River improvements began as early as 1838 with the deepening, widening, and straightening of the Des Moines Rapids at Keokuk, Iowa. In 1866, the federal government assigned the Corps the mission to develop a 4-foot-deep channel between Minneapolis, Minn., and St. Louis, Mo. Before the project was complete, Congress authorized the Corps to begin work on a 4.5-foot channel project. In 1907, Congress mandated that the project be increased to a 6-foot depth from the mouth of the Missouri River to Minneapolis.

In the early 1900s, river improvement organizations, special interest groups, and political officials, were pressuring for a deeper, wider, 9-foot channel. Despite its controversy, Congress passed the 1930 Rivers and Harbors Act ordering that the existing 6-foot Upper Mississippi River channelization project be “modified so as to provide a channel depth of nine feet at low water with widths suitable for long-haul common-carrier service.” At that time, the Army Corps also took over responsibility for improvements made to the Illinois Waterway by state and local interests that had depleted their construction funds.

Between 1930 and 1940, the U.S. Army Corps of Engineers constructed the Upper Mississippi River and the Illinois Waterway 9-Foot Channel Project which transformed the rivers into reliable, safe passageways. The system is most often compared to a stairway with the “treads” being the pools of water created by a series of dams along the rivers. The “risers” are the locks which act as elevators to carry boats from one river pool to the next. The system of locks and dams provide what the rivers in their natural states couldn’t – a dependable nine-foot depth for commercial navigation.

Today, the Upper Mississippi River – Illinois Waterway Navigation System includes 37 locks and 1,200 miles of nine-foot deep navigable waterway in Illinois, Iowa, Minnesota, Missouri, and Wisconsin. The U.S. Army Corps of Engineers manages the 37 locks and dams on the Mississippi and Illinois rivers providing a water stairway of travel for commercial and recreational traffic from Minneapolis-St. Paul, Minn., to St. Louis, Mo., and from Chicago to its confluence with the Mississippi River.

Maintaining the waterways is a shared task of the districts of the Corps’ Mississippi Valley Division.

On the northernmost portion, the St. Paul District maintains 243.6 miles of nine-foot navigation channel and operates and maintains 13 lock and dam sites on the Upper Mississippi River from Minneapolis to Guttenberg, Iowa.

Rock Island District maintains 314 miles of nine-foot navigation channel and operates and maintains 12 lock and dam sites on the Upper Mississippi River from Dubuque, Iowa, to Saverton, Mo. The District also maintains 268 miles of navigation channel and operates and maintains eight lock and dam sites on the Illinois Waterway.

The St. Louis District maintains 300 miles of nine-foot navigation channel and operates and maintains 4 lock and dam sites on the Upper Mississippi River from Saverton, Mo., to Cairo, Ill. The District is also responsible for maintaining the nine-foot navigation channel on the lower 80 miles of the Illinois River.

The Chicago District maintains the Chicago Lock between the Chicago River and Lake Michigan.