Many databases containing items from a variety of locations allow users to use a drop-down menu to view an inventory of specific locations.
Make certain you check out any listing that could be statewide or for more than one location. I almost missed an 1878 farmers’ directory in Illinois because it was classified as a “various” location. 
Would you be so kind as to reveal where you found this farmers directory? I have great-grandparents that lived in Hanover twp. Cook County and am hard pressed to find information about them other than census records.
This one from 1878 is a statewide one that is on Ancestry.com. It appears to be incomplete–which I mentioned briefly in a post on my Rootdig blog http://rootdig.genealogytipoftheday.com/?p=243
Hi Marge. I live in Elgin, close to the Hanover Township line. I also have access to directories that I believe include Hanover Twp. Can you post your ggrandparents names and the time frame of when they lived in Hanover Twp?
Judy