It takes a bit of hiking to get there, but it's well worth it. Enjoy the peaceful surroundings.
Additional info: http://www.dupageforest.com/Conservation/ForestPreserves/Waterfall_Glen.html
East on Bluff Rd from Lemont Rd, just south the I-55 interchange. It is located in Waterfall Glenn Forest Preserve.
Directions from the Nearest Address
Hours Spring Open
Daily open from 1 hour after sunrise to 1 hour after sunset
N 41deg 41.378 W 087deg 59.420
Map Link: Waterfall Glenn Well
760, Kearney Rd, Lemont, IL 60439, US