A theoretical model of farmland valuation is developed that allows urban sprawl to affect farmland values through the conversion of farmland to urban uses, shifts in production to higher-valued crops, and the speculative effect of urban pressure on farmland values. This model is estimated using county level data in the continental United States. Evidence is found for all three effects of urban sprawl on farmland values, with a significant contribution of urban pressure on net agricultural returns around major urban centers. Ancillary evidence supports that the latter effect is attributable to shifts to high-valued crops.