Opening in segments in the mid-1960's, Interstate 270 in Illinois extends 14.97 miles1 between the Missouri state line and the Interstate 55/70 interchange north of Troy. The freeway provides a vital link across the Mississippi River via the New Chain of Rocks Bridge, connecting Florissant and other nearby St. Louis suburbs on the Missouri side with Granite City, Glen Carbon, and Edwardsville lying on the Illinois side. The Illinois portion of I-270 makes up nearly 30 percent of the 50.6-mile loop around the north, west, and south sides of the St. Louis area.
Interstate 270 Illinois Guides
A $104-million project was let on June 17, 2011 by IDOT to replace the ailing Chain of Rocks Bridge. The bridge takes I-270 across the Chain of Rocks Canal, a navigable channel for the Mississippi River. Work commenced on October 31, 2011, with the original eastbound span demolished on January 20, 2015. Work continued through summer 2015.2
- FHWA Route Log and Finders List, October 31, 2002
Page Updated 03-10-2015.