The regionalization of services using a hub-and-spoke model has the potential to minimize unnecessary competition and better utilize scarce health care resources in rural areas. Hub-and-spoke models could be particularly useful for supporting the delivery of essential specialty services that are increasingly threatened in rural communities. The objectives of this project are to: 1) provide information on the development of regional hub-and-spoke models for essential specialty services through case studies of identified models for maternity, oncology, and substance use services, and 2) analyze how hub-and-spoke models could be applied to increase the sustainability of essential specialty services in Critical Access Hospitals (CAHs).