The ethnographic and ethnohistoric records from the Northern and Canadian Plains indicate that a variety of plants were utilized by past peoples. These accounts provide two important insights into plant use in this region where very little archaeological evidence exists for plant utilization. First, plant processing tools are most likely to be unmodified lithic tools that may escape our recognition. Second, a variety of plants, which can be identified via starch grain analysis, were processed with these tools. This project analyzed the residues from two unmodified lithic grinding tools, identified as possible plant processing tools, for starch grains. Our results indicate that not only were a nuinber of wild plant species, such as choke cherry (Prunus virginiana), saskatoon berry (Amelanchier alnifolia) and likely prairie turnip (Psoralea esculenta), processed with these implements, but so too was maize (Zea mays). These results not only provide important insight with respect to identifying a tool class, plant use, and trade within our study area, but also provide an exceptional window into the use of wild plant species, an aspect of human history that is poorly understood in many regions of the world in addition to the Northern Plains.