|SBI Route 181 was Palestine to US-50 near Vincennes IN. This was changed to IL-33 in 1948.|
|SBI Route 182 was Centralia to IL-37. In 1941 IL-161 was extended east from Centralia replacing IL-182.|
|SBI Route 183 was Sesser to Whittington. In 1984 this was changed to IL-154 as an extension of that route. In 1970 several creeks were dammed and Rend Lake was formed. IL-183 was rebuilt to bridge this new lake.|
|SBI Route 184 was (and IL-184 still is) Mulkeytown to Royalton in Franklin County.|
|SBI Route 185 was Bluff City to Farina. In 1949 it was extended NW to Hillsboro. The part from Bluff City to and thru Vandalia was on US-40, and the rest on an unnumbered route.|
IL-185 was the last SBI Route in IL.
All further numbers were assigned after the SBI program ended.
|IL-186 was used from 1938 to 1945 on a road later numbered IL-170 from Seneca to Budd in LaSalle and Livingston Counties.|
|IL-190 was used on the East-West Tollway from the Tri-State Tollway to Sugar Grove from 1966 to 1971. This route had been Toll-US-30 before IL-190. In 1972 IL-190 was changed to IL-5, and then in 1990 it was changed again to I-88.|
|I-190 was used on the spur into O'Hare Airport after 1980. Previously this spur had been IL-594 (1971 to 1980). From 1960 to 1970 IL-194 was used on the Airport Spur, until IL-194 was extended west on the NW Tollway.|
|IL-192 was used in 1955 to designate the old alignment of IL-92 from US-67 to west of Edington in Rock Island County. This is still the same route.|
|IL-194 was used on the Kennedy Expressway in Chicago from the Edens Junction into O'Hare Airport 1960 to 1970. In 1971 IL-194 from the Tri-State into the airport was changed to IL-594 (Later I-190), and IL-194 was extended west on the Northwest Tollway to IL-53 near Schaumburg. In the mid 1970's I-90 was rerouted to it's current route on the Kennedy and Northwest Tollway, and IL-194 was no more...|
|IL-199 was used from 1969 to 1980 on a road from US-67 to IL-92 in Milan and Rock Island. This was changed to IL-92 when IL-92 was rerouted in 1980. This was the freeway along the river.|