The Illinois Waterway system consists of 336 miles (541 km) of water from the mouth of the Calumet River to the mouth of the Illinois River at Grafton, Illinois. It is a system of rivers, lakes, and canals which provide a shipping connection from the Great Lakes to the Gulf of Mexico via the Mississippi River. The Illinois and Michigan Canal opened in 1849. In 1900, the Chicago Sanitary and Ship Canal replaced it and reversed the flow of the Chicago River so it no longer flowed into Lake Michigan.