Four small prairies located on Illinoian till in Macoupin County, Illinois were studied to determine their floristic composition. All of the prairies were less than 1 ha in size. Big bluestem (Andropogongerardii) and little bluestem (Schizachyrium scoparium) were the dominant grasses, while common forbs included Echinacea pallida (pale coneflower), Ratibida pinnata (dropping coneflower), Solidago nemoralis (field goldenrod), and Dalea purpurea (purple prairie clover). The prairie flora consisted of 159 taxa in 45 families. Exotic species accounted for 14 species, while eight woody species were found. Perennial grasses accounted for about 25% of the total cover and importance value. One of the prairies is protected, the Roderick Prairie Nature Preserve.