We developed national projections through 2060 of participation for 17 outdoor recreation activities. The projections were made under futures that vary by population growth, socioeconomic conditions, land use changes, and climate. We used a two-step approach to project the number of participants and the days of participation. The estimation step yielded national-level statistical models of adult participation rate and days of participation by activity. The simulation step combined the models with external projections of explanatory variables at 10-year intervals to 2060. Per capita estimates for participation and days were then combined with population projections to derive estimates of participants and days of participation by activity. Results were derived across three 2010 Resources Planning Act Assessment scenarios that each feature three associated climate futures. Findings indicated that outdoor recreation will remain a key part of the social and economic fabric of the United States.