The preserve is dominated by steep Mississippi River limestone bluffs and ravines. On top of the bluff lies a thick coating of windblown loess soil. This parcel of land has grown into a hill prairie of grasses and forbs characteristic of the tallgrass prairie, and varied by snatches of fire-resistant trees such as the bur oak.
The preserve is home to a wide variety of species found in few other location in Illinois. Some of these include big bluestem grass, plains scorpion, cactus, skinks, and fence lizards.
The upland or hill prairie was once the dominant ecosystem for much of the land that became the U.S. state of Illinois, the Prairie State. The state's Department of Natural Resources, which owns the prairie parcel, describes it as containing "the largest complex of the highest quality, essentially undisturbed loess hill prairies along the Mississippi River in Illinois." Most of the prairie acreage that makes up this parcel apparently remained un-plowed during the pioneer years of the 1800s.