The loss of nitrogen fertilizer into the atmosphere and waterways is of increasing concern for policy makers. This study conducts a cost-effective analysis (CEA) to determine the best strategies, and areas, to reduce nitrogen losses in South Dakota. This form of analysis is done by spatially comparing the amount of reductions per acre across the state, assuming alternative mitigation strategies and adoption rates. Using environmental factors, (Climate type, soil texture, soil organic carbon, soil drainage, soil pH and crop type), and management decisions (no till, conventional till, reduced till, crop rotations, and application timing), we assess the best areas and methods in South Dakota that can be targeted with management changes to gain the most cost effective continuous improvement in nitrogen losses. The Environmental Policy Integrated Climate (EPIC) model was used to simulate the homogeneous response units to changes in nitrogen management practices and assess nitrogen losses. Simetar was then used to derive certainty equivalence values for changes in nitrogen loss and producer returns from changes in nitrogen management.