As part of its ongoing research into agricultural policy and natural resource use, the Resources and Technology Division of USDA's Economic Research Service developed the U.S. Agricultural Resources Model (USARM). This partial equilibrium, comparative static programming model provides estimates of effects on the location, production, and prices of principal crops, commodity program participation, and the use of agricultural inputs resulting from changes in resource constraints, prices, and policy parameters. This report documents USARM including model justification, description of model equations, and discussion of the method of calibration.