The Polaris Project: for a world without slavery supports the National Human Trafficking Resource Center. This web site can answer many of your questions. It includes state-by-state resources.
“Mission to Central America: Flights of the Unaccompanied Immigrant Children to the United States,” November 2013, United States Conference of Catholic Bishops
A Treacherous Journey; Child Migrants Navigating the U.S. Immigration System from KIND (Kids in Need of Defense) and Center for Gender & Refugee Studies
“The Flow of Unaccompanied Children Through the Immigration System: A Resource for Practitioners, Policy Makers, and Researchers from Vera Institute of Justice, Center on Immigration and Justice
“House Tackles Human Trafficking,” by Maya Rhodan, May 20, 2014, Time magazine.