This 88-page report presents new data analyzed for Human Rights Watch by the Transactional Records Access Clearinghouse (TRAC) of Syracuse University. The data show that 53 percent of the 1.4 million transfers have taken place since 2006, and most occur between state and local jails that contract with the agency, known as ICE, to provide detention bed space. The report's findings are based on the new data and interviews with officials, immigration lawyers, detainees, and their family members.