The conference included small public and private high schools with enrollments between 75-1,000 students in Bureau, Boone, Carroll, DeKalb, Jo Daviess, Kane, Lee, McHenry, Ogle, Stephenson and Winnebago counties.

The name Upstate Illini was originally given to a collection of 15 schools primarily coming from five conferences, the Blackhawk, Route 72, Northwestern Illinois, SHARK and US Grant.

The 15 original teams included: Ashton, Chadwick, Durand, Elizabeth, Franklin Center, Hanover, Leaf River, Milledgeville, Mt.

Eventually talks for a re-branding of the Northwest 8 took place in 1987, due to the fact that it had grown to 12 teams and was looking to expand beyond that number.

In 1988, the Upstate Illini Conference was reconstructed and schools from the Northwest 8 joined, competition for all sports, with the exception of football, was established.

Based on these new additions, three divisions were formed West - Dakota, East Dubuque, Galena, Lena-Winslow, Orangeville, River Ridge, Stockton and Warren.

East - Ashton-Franklin Center, Durand, Kirkland-Hiawatha, North Boone, Pecatonica, Rockford Lutheran and South Beloit.