"Laws that restrict where registered sex offenders may live have become increasingly popular during the past decade. As of 2007, some 27 states and hundreds of municipalities had enacted laws that bar sex offenders from residing near schools, parks, playgrounds and day care centers. The specified distance from a school or other venue is typically 1,000 feet but varies from 500 to 2,500 feet, depending on the jurisdiction. Residency restriction laws have led to some unanticipated and unintended consequences. In many locations - most noticeably in urban areas - the restrictions have created overlapping exclusion zones that severely limit where offenders can live. In some cities the only acceptable sites are in high-crime neighborhoods or commercial zones. Even when residential areas are available, sex offenders just released from prison may not be able to find affordable housing in those areas. If unable to find legal housing, offenders may report false addresses, become homeless or go underground. Others may be forced to live in rural areas with less access to employment or mental health services. Even in rural areas where schools and day care centers are more geographically dispersed, most unrestricted land is forest or farmland."
National Institute of Justice: http://nij.gov/