A nice, albeit small, collection of boulders is nestled down inside this tight canyon. Look for classics such as the gorgeous Yosemite Slab v0, the brilliant holds on Juicy Fruit v2, the thuggy Body Karate v8, and O.B.D. v6, among others.
The rock is the famous fine grained sandstone of southern Illinois, which is bullet, but with less friction than the sandstone in, say, Chattanooga.
For those who are well travelled, grades may puzzle you in this area. Speaking as an outsider, they seem to be largely a result of the unique local bouldering culture. Perhaps this will change at some point. For now, take the grades with a grain of salt, check your ego at the door, and just enjoy these wonderful boulders.

N.b.: I noticed that the bouldering hasn't been recorded well here (as to date, just 2-3 boulders have been posted), and the boulders do not easily fit into the rope route categories already listed above. This is an attempt to make it easier to post problems, because this really is a great little area worth visiting. If you have an alternate idea, or if I missed where this has already been done, please send me a PM (not a comment - I may not see it). Thanks, and safe travels.

Per directions on main page.
There are several bouldering spots close to the Jackson Falls canyon. For instance, The Roost is more easily thought of as a separate area.
The boulders on this page should be those actually in the canyon, starting at the Reefer Madness area back up towards the falls, where Praying Mantle and OBD are.