Elephant Rocks is a pretty good bouldering area in Southeast Missouri, about an hour and a half from St. Louis. The rock is a large grained granite, which can be quite sharp and abrasive. Very good for friction though.
The park can be really crowded with family tourists, but I have yet to see any other climbers there. Because of the crowds, climbing is only recommended on weekdays. Also, roped climbing is prohibited within the park.
Getting There
From St. Louis, take 21 (Tesson Ferry) south, and follow it for about an hour and a half. There are a few turns, so make sure you follow the signs that say Hwy 21. After the town of Bellevue, the park i well signed and on the left.
The Classics
Mountain Project's determination of some of the classic, most popular, highest rated routes for Elephant Rocks State Park:
This is a great bouldering area and I was always surprised it didn't get more use from St. Louis/Missouri climbers.
I also think there is a faster way to get there. It is a little less direct but faster because I always found it tough to pass slow trucks on Hwy 21. From STL take I-55 S -> 67 South -> Hwy 32 West -> 21 South right to the park.
Although it has been a few decades since Elephant Rocks was my main area, I have to agree with Joes' assertion as to the fastest route. It's nice to reminisce about the 70's when we would drive down from St.Louis before dawn, drop some 'cid and boulder at dawn...Good Times!
Looking back, I realize that climbers all over the country travel 1.5hrs to get to where they want to climb, TIA or STL. Only now I have to hike for at least 30 minutes. At E-rocks you trip over the curb and hit your head on a boulder problem.