A variety of nonprairie landscapes, including pastures, crop fields, and unmanaged seral ground, are being restored to native prairie on a yearly basis. Seldom is the seed bank associated with these nonprairie lands taken into account in the restoration process. We examine the seed bank potential of nonprairie lands and the relationship between aboveground vegetation and seed bank composition at the largest grassland restoration east of the Mississippi River, the Midewin National Tallgrass Prairie (U.S.A.), by surveying six land management histories: remnant prairie, restored prairie, new pasture, active pasture, old field, and crop field. Both aboveground vegetation and seed bank composition varied with land management history. However, species composition of aboveground vegetation differed significantly from the species composition of the seed bank irrespective of land management history. Aboveground vegetation carried a higher proportion of the seed bank flora than vice versa. In contrast to seed banks of other types of grasslands, the seed bank of historical prairie lands in the U.S. Midwest, irrespective of subsequent land-use history, is not a viable source of species for restoration of tallgrass prairie. A deficiency of many species in the seed bank flora, coupled with an abundance of weedy, often nonnative species, limits the potential contribution of the seed bank to restoration of a prairie vegetation community. Nevertheless, seed bank studies can provide a cost effective method to detect problematic species (i.e., weedy and/or invasive species) and therefore provide a window into the restoration potential of nonprairie lands.