The OJJDP operates under a statutory mandate to support state, local, and tribal efforts to prevent delinquency, address youth victimization, and strengthen the juvenile justice system nationwide. In FY 2019, the Office awarded more than $323 million to support state, local, and tribal efforts to deter delinquency and safeguard children. This report summarizes OJJDP's activities to promote youth mentoring and address gang and gun violence, substance use disorders, and the maltreatment and exploitation of children. OJJDP also supported the work of juvenile prosecutors and enhancements to community supervision and reentry programs. Each chapter describes how OJJDP supported research and data collection, provided technical assistance, and shared the latest resources with the juvenile justice field.