Right on 26,000 acre Carlyle Lake and only about and hour from St. Louis. The shower houses/Restrooms could be better (no soap for your hands in either womens or mens). But they have a great pool, and nice hiking trails! Big level campsites, some border the big Lake.
It's a lot more useful, especially for those doing searches, if you mention that Eldon Hazlet State Park is in Illinois.
The web site:
Eldon Hazlet SP (Illinois) (http://dnr.state.il.us/lands/Landmgt/PARKS/R4/ELDON.HTM)
Thanks for the review! :)
Austin