From today, young offenders here will no longer be sent to adult prisons.
Before now, all 17 year old boys sentenced by the courts have been detained at Wheatfield, an adult prison in Cherry Orchard.
But Children's Minister Katherine Zappone says they will now be held instead at the Oberstown Children Detention Campus in Lusk.
Minister Zappone has also announced that St Patrick's Institution on the North Circular Road will be shut down definitively from next Friday April 7th.
The Irish Penal Reform Trust has welcomed the decisions as a "momentous" move towards ending the damaging practice of sending children to adult prisons.