If you want to learn more about juvenile justice in America, these national organizations are a good place to start.
The National Partnership for Juvenile Services
NPJS provides professional development and technical assistance to promote best practices and standards in the field of juvenile justice and delinquency prevention to positively impact youth, families, and communities.

Coalition for Juvenile Justice
The Coalition for Juvenile Justice (CJJ) is a nationwide coalition of State Advisory Groups (SAGs), organizations, individuals, youth, and allies dedicated to preventing children and youth from becoming involved in the courts and upholding the highest standards of care when youth are charged with wrongdoing and enter the justice system.
Juvenile-in-Justice

Juvenile-in-Justice is a collection of images, interviews, audio documents, and texts created over a dozen years, at 300 sites in 35 states, drawn from the lives of more than 1,000 kids. They work with educational institutions and non-profits to better understand and/or explain the needs, policies, strategies, and resources required to facilitate better outcomes for the 53,000+ children in custody every day.
Annie Casey Foundation’s Juvenile Detention Alternatives Initiative

Juvenile Detention Alternatives Initiative (JDAI)® is a network of juvenile justice practitioners and other system stakeholders across the country working to build a better and more equitable youth justice system.