Here are a couple:
(312) 341-3483
Mike Parnells Magnum Scuba
14 11th St, Chicago, IL 60605
(773) 348-3999
Underwater Safaris On Lincoln
2950 Lincoln Ave, Chicago, IL 60657
(773) 728-2232
Innerspace Expeditions Limited
931 Leland Ave Apt 405, Chicago, IL 60640
(773) 622-9851
Aqua Shop
3224 Harlem Ave, Chicago, IL 60634
(708) 442-4388
Djs Scuba Locker Incorporated
7840 Ogden Ave Ste, Lyons, IL 60534
And on the southern end of Chicago:
(219) 322-7222
Gooses Scuba Shack
1490 Joliet St, Dyer, IN 46311
(219) 942-0016
Lake County Divers Supply
305 Main St, Hobart, IN 46342
(708) 226-1614
Scuba Emporium
16336 104th Ave, Orland Park, IL 60467
(708) 599-2630
Scuba U
7113 79th St, Burbank, IL 60459
(219) 477-4454
Scuba Tank
55 Franklin St, Valparaiso, IN 46383
(312) 341-3483
Mike Parnells Magnum Scuba
14 11th St, Chicago, IL 60605
(708) 442-4388
Djs Scuba Locker Incorporated
7840 Ogden Ave Ste, Lyons, IL 60534
(815) 939-7797
Haigh Enterprises Limited
2738 2000n Rd, Kankakee, IL 60901
(815) 937-1413
Purrfect Scuba
220 Kinzie Ave, Bradley, IL 60915