Oldcastle (Welsh: Yr Hencastell) is a small village in Monmouthshire, south east Wales.
Oldcastle is located six miles north of Abergavenny just off the A465 Abergavenny to Hereford road.
The village is on the River Monnow and very close to the Black Mountains and sits right next to the Wales-England border https://www.geograph.org.uk/photo/73948.
The village is associated with John Oldcastle of an old Herefordshire landowning family through the medieval period.