"In the first six months of FY2016 [Fiscal Year], apprehensions of unaccompanied alien children (UAC) at the U.S.-Mexico border have approached levels close to what they were in FY2014 when such migration flows reached what were characterized as 'crisis' proportions. Unaccompanied alien children are statutorily defined as children who lack lawful immigration status in the United States, are under age 18, and lack a parent or legal guardian in the United States or a parent or legal guardian in the United States who is available to provide care and physical custody. They most often arrive at U.S. ports of entry or are apprehended along the U.S.-Mexico border. Less frequently, they are apprehended in the U.S. interior and determined to be juveniles and unaccompanied. UAC treatment and processing in the United States are governed by several statutes and a legal settlement. Between FY2011 and FY2014, apprehensions of unaccompanied alien children at the U.S.-Mexico border increased each year: from 16,067 in FY2011 to 24,481 in FY2012, 38,759 in FY2013, and 68,541 in FY2014. […] At the close of FY2014, the Border Patrol had apprehended more UAC than in any of the previous six years and close to four times as many as in FY2011. After reaching a peak in FY2014, total UAC apprehensions dropped to 39,970 (a 42% decline) in FY2015. Yet, in the first six months of FY2016 they numbered 27,754, a figure close to the amount (28,579) for the same period of FY2014. In comparison, UAC apprehensions numbered 15,616 during the first six months of FY2015."
CRS Insight, IN10493
Federation of American Scientists: http://www.fas.org/sgp/crs/index.html