This paper presents the methodology, assumptions, and data used to generate regional and national environmental benefit estimates of the USDA's Conservation Reserve Program (CRP). It's assumed that, without the program, production and conservation practices on CRP lands would be the same as those used on surrounding lands. When range and forest lands are (are not) included as land-use options, 54 (71) percent of the CRP land would be in crop production—which is consistent with past analyses. Soil erosion would be 222 to 248 million tons per year—about 11 percent—higher than the current level. Benefits are estimated by applying environmental benefit models, estimated in previous analyses, to the CRP's estimated effect on erosion and wildlife habitat. Nationally, the CRP is estimated to provide $1.3 billion in annual benefits, which represents 75 to 80 percent of the program's cost. In seven of the 10 USDA Farm Production Regions, the CRP's environmental benefits exceed costs. Thus, reallocating acreage to these regions could increase net program benefits. However, because many benefits could not be estimated, one cannot conclude that regional and national benefits do not exceed costs.