In most states persons accused of violating the law before they are 18 years of age are under the jurisdiction of the juvenile courts, and persons accused of violating the law when they are 18 years of age or older are under the jurisdiction of the criminal courts. Some states begin prosecuting persons as adults in the criminal court system when they are 17 years of age, and some states begin prosecuting persons as adults in the criminal court system when they are 16 years of age.

But all states have transfer laws that permit or require criminal prosecution of some young offenders—even though they are still of juvenile age, as defined by the state’s laws. Transfer laws vary from state to state, but generally fall within three categories: (1) judicial waiver laws that allow juvenile courts to waive jurisdiction on a case-by-case basis; (2) prosecutorial discretion or concurrent jurisdiction laws that define a class of cases that may be brought in juvenile court or in criminal court—usually at the discretion of the prosecutor; and (3) statutory exclusion laws that grant criminal courts exclusive jurisdiction over certain classes of cases involving juvenile-age offenders.

The laws that govern when a person of juvenile age may be prosecuted as an adult in the criminal court system are generally located in a state’s statutes.

In Iowa, the jurisdiction of juvenile courts typically covers individuals who are accused of violating the law before they reach the age of 18. However, Iowa does have transfer laws that allow for the prosecution of juveniles as adults under certain circumstances. These transfer laws include judicial waiver, prosecutorial discretion, and statutory exclusion. Judicial waiver allows juvenile courts to waive their jurisdiction and transfer a juvenile case to adult criminal court based on factors such as the severity of the offense and the juvenile's age, criminal history, and amenability to rehabilitation. Prosecutorial discretion or concurrent jurisdiction laws enable prosecutors to decide whether to file certain cases involving juveniles in juvenile or adult court. Statutory exclusion laws in Iowa automatically exclude certain serious offenses from juvenile court jurisdiction, meaning that juveniles charged with these offenses are directly prosecuted in adult criminal court. The specific age at which juveniles may be prosecuted as adults and the types of offenses that trigger these transfer provisions are defined in Iowa's state statutes.