[2] Before human alteration, water flowed westward from LaPorte County, Indiana, along the Little Calumet River, made a hairpin turn at Blue Island, and flowed east along the Grand Calumet into Lake Michigan at the Miller Beach community of Gary, Indiana.

The Little Calumet River breached its levee and flooded portions of the towns of Munster and Highland, Indiana.

A canal extending it, legendarily claimed to have been created by voyageurs at the site of a frequent portage, was dug connecting the two Calumet Rivers at the point where the name now changes from Grand to Little.

Three Rivers County Park is located on the border of Gary and Lake Station where I-65 meets the Borman Expressway.

[6] It used to continue westward to Illinois as the Little Calumet River, but construction of the Burns Waterway in 1926 diverted its flow into Lake Michigan.

The Little Calumet River has been undergoing construction of a $200 million flood control and recreation project by the Chicago District of the U.S. Army Corps of Engineers since 1990.

When complete, the project will protect over 9,500 homes and businesses in the towns of Gary, Griffith, Highland, Hammond, and Munster in Indiana, and prevent nearly $11 million in flood damage annually.

On September 15, 2008, the remnants of Hurricane Ike released heavy rain which flooded the banks of the Little Calumet River.

Recently, a new levee, along Northcote Avenue in Munster, is being built to protect residents from future floods.

The Cal-Sag Channel serves barge traffic in what was an active zone of heavy industry in the far southern neighborhoods of the city of Chicago and adjacent suburbs.

As of 2006 it was also used more as a conduit for wastewater from southern Cook County, including the Chicago-area Deep Tunnel Project, into the Illinois Waterway.