Similar in concept to a watershed, a foodshed demarcates the area from which a population derives its food supply. This concept can be applied in a local context to improve understanding of how local food systems can contribute to a more sustainable agriculture. We tested two approaches to mapping potential local foodsheds and estimating the theoretical minimum distance within which food needs could be met for Rochester, New York: 1) an iterative process of intersecting buffers with estimated food production and 2) an optimization model. For simplicity sake, the model uses corn grain as a proxy for food. Results from the buffering approach indicate that the 240 Mg of corn needed to meet the caloric requirements of the Rochester metropolitan area could be produced within 26.6 km of the city limits. The optimization approach indicates that the average distance within which caloric requirements could be met is 10.7 km, and also calculates foodsheds for two neighboring smaller cities. Because of the ability to consider multiple cities simultaneously, optimization is the superior approach. Future research will apply the optimization approach to a complete diet across a wider geographic area.