To implement a successful air resource management program, an air quality control region should be large enough to encompass most air pollution sources as well as most people and property affected by those sources. The boundaries should also include those locations where present development creates, or where projected urbanization and industrialization will create, significant air pollution problems. Finally, the region should be compatible with or hopefully even foster unified and cooperative governmental administration of the air resource. The proposed Metropolitan Cheyenne, Wyoming, Intrastate Air Quality Control Region was designed to satisfy, in the best way, these requirements.