For old, see what you can find on the old foundry of Barnhart Brothers & Spindler.

I think both Fred Goudy and Oz Cooper lived and worked in Chicago for at least part of their careers. Cooper, if I recall correctly, was deeply connected to the sign writing tradition in Chicago. Sorry I'm so sketchy on details; maybe I'm remembering some about Cooper's biography from "Behind the Typeface" :-)

Some random ones off the top of my head:
Cooper
Goudy and Dwiggins spent some time there
Robert Hunter Middleton is a big, overlooked one
Rick Valicenti, Patric King, Chester (pre-vllg) and other Thirsttype people.
Andrew Byrom does rad sculptures
Barry Deck was there for a while
Silas Dilworth worked there until a few summers ago
I designed the first half of Alright Sans there and am moving back soon.

Thanks so much guys. This a great start. We're actually working with rick, who spoke at our event, to do a few spreads. (In case any were wondering, the event is here http://tinyurl.com/yj7csp9) as well as Jeremiah Chiu from Plural. The newer community we definitely have covered, although some of those names are a surprise to me! It's the years farther back that is harder to figure out but this is a great start, and again, thank you.

jackson, I was sad when Silas pulled out of here. His studio was right around the corner from my place and I never had the chance to bump into him. Although came close as I think he was invited to teach a type class at the same portfolio school I'm doing a class at.

James Greishaber (Typeco) is based there in Chicago.

Will - Ascender's type designers include Jim Ford & Terrance Weinzierl (both based out of our office in Elk Grove Village), and Steve Matteson - who grew up in Oak Park but now lives in Colorado.

Don't forget Will Ransom and John M. Bergling...

I worked in Chicago for three great months ten years ago, but that was before I really began designing type.

I think I also remember something about Bruno Maag spending some time in Chicago, pre-Dalton Maag.