Illinois State Museum

prairie diorama
Prairie Diorama
Illinois State Museum
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Central Prairie
McLean County, 1673

This is a tallgrass prairie in the summer of 1673. The Grand Prairie once covered most of the northern two-thirds of Illinois. Early European explorers and settlers were amazed by the seemingly endless sea of grasses and wildflowers—some so tall that a man on horseback could ride through unseen.

“We now took up our journey across the plains...Fields of prairie frequently spread before the eye, like the boundless expanse of the ocean… Its apparent boundary is the horizon… So vigorous a growth of grasses and flowering plants, covers these plains, that in several places, we found them to overtop our shoulders, sitting on horseback; a proof, if any proof were wanting, of the strength and richness of the soil."
— Henry Rowe Schoolcraft 1821

Regular fires maintained a dense cover of prairie grasses, preventing the invasion of woody trees and shrubs. Over thousands of years, the prairie's annual cycle of growth and decay created deep, fertile soil.

This reconstruction is based on historic records, archaeological evidence, and studies of the geology and ecology of the Grand Prairie Division of central Illinois.

To read more about the Illinois Prairie, go to the Museum's Illinois Prairie Web Exhibit and to Prairies in the Prairie State Web exhibit.