Rath Esa
Garristown's hill was a hillfort before recorded Irish history - a defensive enclosure of the kind built across Ireland during the Iron Age. The name Rath Esa is said to come from a Celtic princess who settled here. In 1736 someone built a windmill inside the remains of the ancient earthworks, which says something about how Irish history layers itself. The windmill base is still standing. The earthworks are still visible around it. The hill has the best view in this part of Fingal.