The purpose of this study was to investigate the state library services in the United States in order to consider what services are needed for regional libraries in Korea. The data were collected from library statistics and library web pages. The analyses particularly focused on examining the residental service and library service of state libraries. The analyses revealed that the state libraries provide funds, services, and training to local libraries, but the service levels are varied among states. State libraries provide state historical information and genealogy information to residential users, and focus on the information needs for handicapped people. Based upon the analysis of U.S. state libraries, Korea regional libraries would provide services different from local public libraries. Also, regional libraries would be operated based upon the regional characteristics.