The bluffs on the Illinois River near Peoria were a mix of oak woodlands and prairie openings in the early 1800s. One of the largest remaining oak woodland areas in Illinois is found here. The bluffs at Forest Park Nature Preserve provide a good example of the original vegetation, although the area was lumbered in the mid-1800s. White oak and shagbark hickory predominate on the drier, upper slopes and ridges; red oak and sugar maple characterize the lower slopes and ravines.

Size: 277,847 acres; 434 square miles

Location: Central Illinois on the Illinois River, Peoria area; Marshall, Peoria, Putnam, Stark, Tazewell, and Woodford counties

Peoria Wilds encompasses the floodplain of the Illinois River, deeply dissected bluffs and hills bordering the floodplain, and relatively flat agricultural areas away from the river. A large tract of forest runs along the bluff to the west of the Illinois River. Nonforested wetlands are concentrated next to the river.

Several hill prairies in this area have been included in the Illinois Natural Areas Inventory. The sun-and wind-exposed west and southwest-facing slopes of hill prairies create a harsh environment more suited to prairie than forest. Few hill prairies have been plowed because of their steep slopes, but they are sometimes grazed.

LANDCOVER : Cropland (46%) is the predominant landcover type at this site, followed by upland woods (20%) and grassland (16%). It ranks low in the percentage of nonforested wetland and has moderate bottomland percentages. The relatively high percentage of water is due to the large lakes associated with the Illinois River and floodplain.

NATURAL AREAS : Woodlands, hill prairies, marshes, fens, and seeps are some of the important natural resources in the 24 Natural Areas located in this RRA.

BIOLOGICALLY SIGNIFICANT STREAMS : There are no BSS streams in this RRA.

HERITAGE SITES :Of the 51 Heritage sites, nearly half are occurrences of significant communities of wetlands, forest, savanna, and prairie. Six plant species, four animal species, one forest block greater than 500 acres, and one rookery occur in this RRA.

STATE AND FEDERAL LANDS : Four state conservation areas and one fish and wildlife area comprise the state land in the RRA. A unit of the Chautauqua National Wildlife Refuge is located here. These public lands are associated directly with the Illinois River.

NATURE PRESERVES : Seven sites are recognized as Nature Preserves. The natural resources includes seeps, fens, hill prairies, and upland forest in deep ravines and on slopes and ridges.

NATURAL DIVISIONS : The natural divisions occurring in the RRA are the Grand Prairie (62%), Upper Mississippi River and Illinois River Bottomlands (30%), and the Illinois River and Mississippi River Sand Areas (7.5%).