In Washington state, the Department of Corrections says 14 inmates are still serving life without parole for crimes committed while they were juveniles.
Seventeen others have been resentenced, and two received new life-without-parole terms.
Before 2014, juvenile offenders were treated the same as adults and would automatically get life without parole for first-degree murder.
In 2014 and 2015, state lawmakers revised a statute to include specific sentencing instructions for 16- and 17-year-old offenders convicted of aggravated first-degree murder to ensure that mitigating factors be considered.
The Legislature also allowed all those convicted before turning 18 and sentenced to 20 or more years in prison to petition for release after 20 years.
The Associated Press is reviewing juvenile life without parole in states after recent U.S. Supreme Court decisions.