Interstate 90 (I-90) in the U.S. state of Illinois runs roughly northwest-to-southeast through the northern part of the state. From the Wisconsin state line at South Beloit, it heads south to Rockford before heading east-southeast to the Indiana state line at Chicago. I-90 traverses through a variety of settings, from farmland west of the Fox River Valley through the medium-density suburban west of O'Hare International Airport, through downtown Chicago, and through the heart of the industrial southeast side of Chicago before entering Indiana.