The development of psychometrically sound measures of the behavior settings in which physical activity occurs is critical to future investigations into the links between environment and physical activity. The primary aim of the proposed project is to develop and evaluate the psychometrics of an inventory to assess the environment and surrounding context of public recreation spaces (PRS). The project focuses on the prevalent and highly used public recreation spaces of public parks and playgrounds. The project begins with a qualitative Delphi surveying process conducted among park/recreational professionals and community residents who are frequent PRS users. Through this process, PRS characteristics (e.g., pathways, open space, seating, services) and context variables (e.g., land uses around PRS, street and sidewalk connectivity to PRS) will be identified. The inventory generated by this process will be tested for feasibility and inter-reliability through direct observation by trained observers of a large sample of differing types of PRS. PRS context variables will also be generated through methodologies applied to the local land use and other databases through geographic information system software. This project will generate a valuable inventory to be used in future research exploring the relation between physical activity/PRS use and PRS design and placement, perhaps ultimately to facilitate better PRS design for the promotion of physical activity.