The closest one to you I believe is Winmakers and Brew 689 W North ave Elmhurst Il 630-834-0507
I would recommend mail order at Midwest Homebrewing in Minnesota they deliver in a couple of days, no sales tax but you do pay for shipping but the cost to drive to Elmhurst, Madison or Milwaukee is expensive probably more than the shipping cost.
Some local bottled water company may sell corboys but I'm not sure. Also don't know what size you want 5 gal or 61/2 I doubt if they would have both sizes .
Ps I live in Mount Prospect IL