SBI Route 26 originally ran from Freeport to Polo, on part of current IL-26. In 1937, IL-26 was extended from Freeport to the WI state line, in place of IL-74, and extended from Polo to Bureau along US-52 to Dixon, and replacing IL-89 from Dixon to Bureau. In 1969, it was extended south to East Peoria replacing IL-87. In northern
Stephenson County, IL 26 originally ran through downtown
Orangeville and the unincorporated community of Oneco. In 1990, it was rerouted onto a new at-grade bypass around the village, decreasing travel time. IL-26 was rerouted onto the nearby I-180 bridge over the Illinois River near Hennepin during the 1990s. The older IL-26 bridge, half a mile south of I-180, was removed after 1999. the old approaches are now local roads, used mainly as access to riverside industries on both banks. ==Major intersections==