Last week I had a good three-stage learning process at the Chicago History Museum's Research Center [formerly the Chicago Historical Society's library] about what detailed fire-insurance-type maps (AKA "Sanborns") are available and where. Do note CHMRC's hours (not extensive) and admission fee ($5 a day or $15 a year).
First, I was introduced to a 1916 map -- black and white, copied from microfilm -- available on computers there and useful for orientation.
Second, there is Robinson's Atlas of the City of Chicago, Illinois, from 1886, which has been republished in full, free and online, in the Encyclopedia of Chicago. This is not the most user-friendly interface but it's manageable. Use the little slider bar verrry carefully.
Start with the Atlas Map close to the extreme left end. Magnify that map (you'll want to magnify everything) to ascertain which section, township, and range of the 1886 city includes your address. (Mine was Section 7, Township 39, Range 11, AKA 7-39-11, lying south of Chicago, north of Madison, east of Western, and west of Ashland, AKA 0 to 1200 North and 1600 to 2400 West in today's numbering scheme, which was not in use in 1886 but it helps to know it.)
Then return to the slider bar and slide it along until you get to the volume associated with your desired neighborhood or address. (Mine was volume 4.) At this point you may find that for no particular reason the map has rotated 90 degrees so that the east-west streets are going up and down. Use the rotator function to get the city headed in the right direction for a change. Then magnify magnify magnify and find the large-type plate number for your subarea. (Mine was 19.)
Continue along the slider to your desired plate number and magnify it as far as you can to see your chosen neighborhood, building by building.
Third, having done this, you can tell plenty but not as much as a full-dress fire insurance map can tell you. For that, visit CHM in person and use their on-table looseleaf binder of indexes to figure out which of their hard-copy atlases are available for which areas and which dates. (Not all areas and dates are covered by a long shot, but most areas seem to get some coverage for at least one date.) These are full-color, with notations on the type of roofing, the size of the water mains, the nature of construction (wood, brick, stone), the number of stories, and on and on. (EOC also has a nice short article by Richard Harris on some more sophisticated ways to "read" the maps.)
If you're the kind that wants icing on your cake, review the looseleaf binder again and then ask for the file folders of readily available images sorted by street name, church name, etc., in hopes of getting a ground-level view of your neighborhood back in the day. I didn't luck out but it's well worth trying.
