I've located two antiquarian map dealers in the Chicago area, and one is in downtown Chicago very close and convenient to where we will be next month.
Harlan J. Berk, Ltd. is primarily a coin shop (Paige!) but they also deal with maps --- enough so that they will be exhibiting at the upcoming Chicago Map Fair (see http://www.chicagomapfair.com/exhibitors)
The store is located at : 31. N Clark st. Chicago, IL 60602 Phone: (312) 609 - 0016 Fax: (312) 609 - 1305 Website: www.hjbltd.com Email: info@hjbltd.com
Collection: http://www.hjbltd.com/maps/maps.asp?inventorygroup=mp
Another area map dealer, George Ritzlin, is a train ride away in Evanston, Illinois (where Northwestern University is). Directions and hours are posted at his website linked below.
George Ritzlin Maps & Prints