Chicago Portage

Chicago Portage
Elevation	589 ft (180 m)
Traversed by	Mud Lake (historic), Illinois and Michigan Canal (historic), Chicago Sanitary and Ship Canal, several railroads, numerous roads including I-55 (Stevenson Expressway)
Location	(historic dividing point) 3100 West 31st Street, Chicago, Cook County, Illinois, US
Range	Valparaiso Moraine
Coordinates	41°50′14″N 87°42′8″W / 41.83722°N 87.70222°W / 41.83722; -87.70222

The Chicago Portage was an ancient portage that connected the Great Lakes waterway system with the Mississippi River system. Connecting these two great water trails meant comparatively easy access from the mouth of the St. Lawrence River on the Atlantic Ocean to the Rocky Mountains, and the Gulf of Mexico. The approximately six-mile link had been used by Native Americans for thousands of years during the Pre-Columbian era for travel and trade.

In the summer of 1673 members of the Kaskaskia, a tribe of the Illinois Confederation, led French explorers Louis Jolliet and Father Jacques Marquette, the first known Europeans to explore this part of North America, to the portage.  A strategic location, it became a key to European activity in the Midwest, ultimately leading to the foundation of Chicago.^[1]

The Portage crossed waterways and wetlands between the Chicago River and the Des Plaines River, through a gap in the Valparaiso Moraine. In 1848, the water divide was breached by the Illinois and Michigan (I&M) Canal cutting through the portage, this was deepened and widened in 1900 by the Chicago Sanitary and Ship Canal which was also used to control the water's directional flow.