If you are looking for a place to car camp, then you may enjoy this park.
Here is a short video of my short walk at Illini State Park.
The Illinois River Valley as it looks today is the result of continual and often dramatic natural changes to the landscape.
Some of the processes that shaped this river and its valley are, literally, as old as the hills. Sandstone and limestone bluffs recall an era, millions of years past, when an ancient sea overspread this region. The Mississippi River once flowed through this valley, before glaciers shifted its course to the west. South of Hennepin, the Illinois River follows the Mississippi's ancient channel. A more recent glacial event sculpted the upper reaches of the Illinois River. Seventeen thousand years ago, glacial meltwaters burst through a rock-earth dam holding back a massive lake, unleashing the Kankakee Torrent, which carved the river valley all the way to Hennepin.
As the glaciers retreated, lichens and plants reinhabited the barren landscape, many of which sprouted from seeds left behind in the glacial deposits. In the 12,000 years since then, rich topsoils accumulated, and complex and varied communities of plants and animals-from lush bottomland hardwood forests and riparian floodplains to tallgrass prairies and woodland spring seeps-have established and flourished here.
The Illinois River Road sites below to enable you to experience how geological transformations have shaped the Illinois River Valley and how, since the end of the Ice Age, dynamic natural communities have become established in the Illinois River Valley.
Located across the Illinois River from the town of Marseilles, the 510-acre Illini State Park lies along the northern edge of the Great Falls of the river, where a drop in streambed gradient creates beautiful roaring rapids. The park itself sits atop an old glacial moraine (elongated ridge-type hill bulldozedup by an advancing Pleistocene glacier) and features a dense hardwood forest of oaks and hickories on the ridge tops, sugar maple, black walnut, and white ash on the slopes, and silver maple and cottonwood in the bottoms, providing diverse habitat for birds and birders. Hikers (and cross country skiers in winter) can take the parks Marasottawa Trail which loops from the Sycamore Grove Shelter on the east end of the park up to the Mallard Bay Shelter and Boat Launch on the east end. LaSalle County birders highlight this trail as one of the best sites in the county for viewing migrating vireos, warblers, thrushes, and other songbirds in fall.
The above information is from http://www.illinoisriverroad.org/byway_story_geology.cfm