"In FY2014, the number of unaccompanied alien children (UAC, unaccompanied children) that were apprehended at the Southwest border while attempting to enter the United States without authorization increased sharply, straining the system put in place over the past decade to handle such cases. Prior to FY2014, UAC apprehensions were steadily increasing. For example, in FY2011, the Border Patrol apprehended 16,067 unaccompanied children at the Southwest border whereas in FY2014 more than 68,500 unaccompanied children were apprehended. In the first 8 months of FY2015, UAC apprehensions numbered 22,869, down 49% from the same period in FY2014. UAC are defined in statute as children who lack lawful immigration status in the United States, who are under the age of 18, and who either are without a parent or legal guardian in the United States or without a parent or legal guardian in the United States who is available to provide care and physical custody. Two statutes and a legal settlement directly affect U.S. policy for the treatment and administrative processing of UAC: the Trafficking Victims Protection Reauthorization Act of 2008 (P.L. 110-457); the Homeland Security Act of 2002 (P.L. 107-296); and the 'Flores Settlement Agreement' of 1997."
CRS Report for Congress, R43599
Federation of American Scientists: http://www.fas.org/sgp/crs/index.html