This Policy Research Brief summarizes longitudinal national statistics on the number and characteristics of persons with mental retardation and related conditions living in state institutions, their movement into and out of those institutions, the costs of state institutions, and the growing numbers of closures of these institutions. Findings are based on data collection by the National Data Set Project on Residential Services located at the University of Minnesota. The brief uses narrative, tables, and graphs to specifically address the following: historical patterns of deinstitutionalization; the total residential care system; resident characteristics (functional assistance needs, age, secondary conditions); resident movement (patterns, characteristics of movers, previous and subsequent residences); state institution costs; and state institution closures (past and projected closures, and selected state plans and policies on closure). The continuing commitment of states to the depopulation and closure of state institutions is projected, with continuing challenges in providing adequate resources for community services for those with high support needs. It is predicted that increasing cost inefficiencies of under-utilized state institutions will lead to even more closures of such institutions. (DB)