Sand Prairie-Scrub Oak Nature Preserve preserves rare remnants of the sandy prairie, scrub oak, savanna, and sand forest landscape that once covered parts of central Illinois. In western Mason County near Kilbourne, the 1,460-acre site was purchased in 1969 and dedicated as an Illinois Nature Preserve in April 1970, and it is managed as a separate unit of nearby Sand Ridge State Forest. Its unusually sandy soil supports dry sand prairies, sand savannas, and sand forests dominated by black oak and blackjack oak. A 2008 study recorded 393 species there, and research in 2015 identified Illinois's first known dwarf chinkapin oak along with notably northern black hickory.