There is growing interest in how US agricultural land use would change if US diets changed. These questions can be driven by interest in reducing environmental impacts of food production or interest in the carrying capacity of land. In particular, the role of dairy as a driver for land use decisions is of interest. This study seeks to understand how diet demands for dairy products may affect US land use. FASOM (Forest & Agricultural Sector Optimization Model) was used to assess agricultural land use changes under 3 diet scenarios. In this model, the endogenous variables include commodity prices as well as production, consumption, export, and import of those primary and secondary commodities. The dependent variable is the allocation of land, and the objective function maximizes the net present value for producers and consumers in the US. The 3 diet scenarios included a 1 cup / person / day increase in dairy. One diet scenario had only this change; the others had decreases, either across the diet or just in sugars and sweetened beverages. In addition, a sensitivity analysis of dairy cow yields and population distribution was conducted. In the base case of FASOM, cereals, corn, hay, and soybeans account for the majority of cropland (35, 25, 8.2, and 21%, respectively). Silage production contributes 3% of land use, and fruits and vegetables are about 1.6% of total cropland. Apportioning crop land uses to dairy, we find that dairy land use accounts for slightly less than 9% of the total. With the diet scenarios, there are modest increases in silage and hay production (up to 14% and 5%, respectively, of existing levels) to accommodate increased dairy demand across all scenarios. These increases are driven by the fact that silage and hay provide relatively high yields at an affordable price (as opposed to pasture – lower yield and low price – or corn – higher yield but higher feed price). Across all scenarios, the relative change in the land use and price of major crops, such as corn and wheat is restricted (less than 1% for the dairy increase alone, less than 5% for other scenarios). The model also indicates that absolute changes to pasture and rangeland use in the United States would be less than 1% across all scenarios.