This chapter discusses a number of data sources that may be of interest to the epidemiologist and public health researcher, although they are not focused exclusively on health issues. The U.S. Census is the basic source of demographic information about people living in the United States and is often used by health researchers to provide contextual information such as the racial makeup or economic status of geographic areas they are studying. The Area Resource File (ARF) contains health, economic, and demographic information drawn from a number of sources and aggregated at the county level. It is also frequently used to provide contextual information for geographic areas. The General Social Survey (GSS) is a telephone survey conducted since 1972 that collects data on a variety of social issues, including alcohol and drug use, sexual behavior, and attitudes toward health issues such as abortion and euthanasia. The ICPSR, located at the University of Michigan, is a repository of data on a variety of topics, many of which are health related, including data from the Health and Medical Care Archive (HMCA) of the Robert Wood Johnson Foundation (RWJF). The Henry A. Murray Research Archive, housed at Harvard University, contains data and ancillary materials from more than 270 longitudinal studies of human development and social change. The Project on Human Development in Chicago Neighborhoods (PHDCN) is a large-scale, longitudinal study of how child and adolescent development is affected by families, schools, and neighborhoods.