Progressive Era campaigns to establish juvenile courts maintained that police and criminal courts failed to distinguish between children and adults. They suggested that law enforcement agencies either sentenced juveniles as if they were adults, imposing excessive punishments, or let kids go, failing to discipline them and encouraging them to commit further crimes. However, this case study of juvenile arrests in turn-of-the-century Detroit indicates that, before the creation of juvenile court, criminal justice institutions had more complex interactions with delinquent youth than has been recognized previously. Boys typically were arrested for very different offenses than were adults, and the police and courts often segregated children and adolescents from the harshest elements of the criminal justice system. The police sought every opportunity to decide the outcome of juvenile arrests themselves, without a court hearing, particularly if boys had committed only status offenses such as truancy or if crime victims decided not to prosecute. When juveniles did appear in criminal courts, judges found ways to soften their experiences, rarely jailing younger boys and instead sentencing some to reform school for ostensible rehabilitation. After 1900, efforts to protect young offenders from criminal justice institutions expanded as specially assigned police officers increasingly sought to discipline delinquents prior to arrest and the courts introduced an unofficial form of probation. Rather than constituting a break from the past, the creation of Detroit’s juvenile court in 1907 mainly made official juvenile offenders’ growing separation from the criminal justice system.