Hi Guys,
I did a quick search and per civilwararchive.com which is based on Dyers Compindium there was no formal CSA regiment from Il. There were two groups unknown size from the AZ territory. "A history of Southern Il from egyptaninaa.com which I believe is sponsered by the Southern univ of Il there were a few men from Southern Il who did cross the border to join CSA regiments. There may of been two Il CSA regiments I just couldnt find them.

Leonard