While the Federal Government does have a hand in juvenile law, namely that of setting guidelines for the states to follow (i.e. Federal Juvenile Delinquency Act) and allocating funds to the states for their compliance (i.e. Juvenile Justice and Delinquency Prevention Act of 1974), the juvenile justice system is really in the hands of the states. It may seem like a trivial distinction, but State courts can actually decide at which age juvenile charges can no longer be filed.
Juvenile rights carry on until the age of 18 in most areas, whereupon a person legally becomes considered to be an adult. In a handful of districts, though, this threshold may be lower. In states like North Carolina and New York, for example, juvenile charges may cease when a child reaches the age of 16.
The incidence of arresting minors and filing juvenile charges may often vary quite noticeably as mediated by children actually committing those acts and the standards of local, county and State police. Other juvenile rights, such as the ability of a defendant under the age of 18 to be tried as a juvenile after having his or her case heard in a regular court of law, are also at the discretion of the states, and therefore, make State-to-State comparison hard. Concerning this example, over a third of states, including Florida, Pennsylvania and Nevada, will apply "once an adult, always an adult" standards to some minor offenders' records.