Policies designed to deliberately control the spread of urban areas are increasing in popularity throughout the United States. Several states, and many local governments in the west, are adopting urban growth boundaries and other containment measures in their land-use planning laws and legislation. Whatever the primary purpose, it is clear that the precise impacts of containment policies are not well understood. This paper reviews the research on urban containment generally, and also examines the experience of such policies in particular metropolitan areas. It discusses some lessons learned and raises relevant research questions for practitioners as well as policymakers at the state and local level.