The Cal-Sag Channel is utilized for inland shipping, recreational boating and drainage purposes in what was an active zone of heavy industry in the Far Southeast Side neighborhoods of the city of Chicago and adjacent suburbs.

As a drainage channel, it is used as a conduit for treated effluent wastewater from southern Cook County, including the Chicago-area Deep Tunnel Project, into the Illinois Waterway.

[1] The canal was initially constructed to a width of 60 feet (18 m), with its eastern end guarded by the Blue Island Lock and controlling work.

[2] With the development of the Illinois Waterway to provide for a standardized inland shipping connection between Calumet Region and the Mississippi River, 160 feet (49 m) passing sidings were built along the canal every three miles in 1936.

The channel was once again widened and improved by the Army Corps of Engineers (USACE) between 1955 and 1965 to its current 225 feet (69 m) to allow use by increasingly large barges.