Arid and semiarid public lands in the southwestern United States are suited for a variety of commodity and amenity production uses such as cattle grazing, hunting, hiking, horseback riding and recreational vehicle driving. This study discusses the development of a model that allocates public lands to different use designations with the objective of optimizing net social benefits subject to activity incompatibility, and budgetary and physical resource constraints. Demand and benefit functions for a system of multiple sites and activities are derived from a sound theoretical specification of consumer behavior. Finally, a programming optimization procedure is employed to determine the optimum allocation of activities to several parcels in the specified resource base for given population levels in areas of interest.