This study investigated the relationship between urban park size and community mental health, focusing on neighborhood crime risk as a mediator. Data were collected for 989 urban parks in Alabama, USA, from the Trust for Public Land's ParkServe database and relevant Alabama cities' Parks and Recreation Department websites. Park size was measured using Geographic Information Systems. The relative risks of various crime types, including violent and property crimes, were provided by the Environmental Systems Research Institute. Community mental health data from the PLACES database were used to evaluate the prevalence of poor mental health in different communities. Guided by the Stress Reduction Theory, we used mediation analysis to explore whether crime risk mediated the relationship between park size and mental health outcomes. Results indicated that the effect of larger park sizes on reducing poor mental health was fully mediated by the indirect pathway through reduced crime risk, though park sizes alone were not significantly directly associated with a lower prevalence of poor mental health. By allocating resources to create and maintain high-quality urban neighborhood parks, policymakers can foster safer environments that contribute to improved mental health across communities, and, ultimately, build essential infrastructure to support the public's mental well-being.
