The Calumet-Saganashkee Channel, usually shortened to the Cal-Sag Channel, is a 16-mile-long (26 km) drainage and shipping canal in southern Cook County, Illinois, operated by the Metropolitan Water Reclamation District of Greater Chicago (MWRD). A component of the Chicago Area Waterway System, it connects the Little Calumet River at its eastern end to the Chicago Sanitary and Ship Canal at its western end.

The Metropolitan Water Reclamation District of Greater Chicago (MWRD), originally known as the Sanitary District of Chicago, is a special-purpose district chartered to operate in Cook County, Illinois since 1889. Although its name may imply otherwise, it is not a part of the City of Chicago's local government but is created by Illinois state government with an elected Board of Commissioners. The MWRD's main purposes are the reclamation and treatment of wastewater and flood water abatement in Cook County to protect the health and safety of citizens and of area waterways. In 1900, the District notably reversed the flow of the Chicago River, and it is currently involved in the large multi-decade construction of the "Deep Tunnel," Tunnel and Reservoir Plan (TARP).