My suggestion is to find locals that know how/where/when to find things in your area. This forum is a good place to start. Look for a Herpetological society that meets within driving distance of where you live, go to meetings, and make friends with people in the know. If there is a major university around (purdue?) go talk to the professor(s) that study reptiles. Chances are that they, or their helpers (grad students) go collecting, as part of their research. They may not want to give you info (afraid that you will go out and "mess up" their study population) but they may help you out if you approach them right.
It is also possible that there just aren't many snakes living near you because of urbanization, agriculture, or severe winters, and you need to make field trips to farther away places that are "crawling" with herps. Ask the guys at the nearest herpetelogical society about it.
I did a quick search:
Hoosier Herpetological Society
http://www.hoosierherpsociety.org
P. O. Box 40544
Indianapolis, IN 46240-0544
Mid-Mississippi Valley Herp Society
Mike Ladato
925 Park Place Dr
Evansville, IN 47715
TRI-STATE AMPHIBIAN & REPTILE ASSOCIATION
http://www.geocities.com/tsara99/tsara2.html
http://herpcenter.ipfw.edu/
Good luck!!