ABSTRACT Large expanses of loess hill prairie were once common along the bluffs of the Mississippi and Illinois rivers of Illinois. These communities occur in forest openings on thick loess deposits overlying bedrock and frequently have expanses of exposed limestone at their margins (glades). Warm season, clump-forming grasses dominate the herbaceous vegetation along with a mixture of prairie and open forest species. Miles Hill Prairie, Monroe County, Illinois is located about 20 km west of Waterloo in the Northern Section of the Ozark Natural Division. Within the prairie, 148 vascular plant species were recorded with 40 species found in the survey plots. Schizachyrium scoparium dominated followed by Andropogon gerardii, Solidago speciosa, Sorghastrum nutans, and Bouteloua curtipendula. Common forbs include Pycnanthemum pilosum, Symphotrichum patens, and Symphotrichum oolentangiense with Cornus drummondii the most abundant shrub, and Torilis japonica the only exotic species in plots. This is a high-quality loess hill prairie that is well maintained by prescribed fire and brush removal. Most species encountered were common to loess hill prairies, with the 19 exotic species being rare and mostly restricted to prairie edges.