The Resource and Agricultural Policy System (RAPS) is upgraded and documented in this technical report. RAPS was developed to estimate the environmental impacts of farming practices and policy in 128,591 National Resources Inventory (NRI) sites in the Central United States (the Corn Belt, Lake States, and Northern Plains). This modeling system integrates the effects of soils, climate, crops, and management practices on several environmental indicators including nitrate runoff and leaching, pesticide runoff and leaching, water and wind erosion, and soil organic carbon. RAPS can be used to provide timely information on the nation's environmental health as it is impacted by agriculture and by changes in agricultural and resource policies.