A total of 47 woody species was found in a vegatation survey of a terrace forest in Clark County, Illinois. Two distinct vegetation zones (low and high terrace) occur on the woodlot, and their composition and ecological trends are discussed. Woody species of the low terrace average 140 stems per acre with a basal area of 125 square feet; it is dominated by Ohio buckeye, box-elder, hackberry, sycamore, silver maple, black walnut, and American elm, in order of Importance Value. The high terrace averages 126 stems per acre with a basal area of 113 square feet per acre, and is dominated by shellbark hickory, box-elder, white oak, white ash, red maple, and red elm.