After reading the interpretation panel in the car park, go through the kissing-gate and down the path by the entrance to the car park, so that you can approach the impressive early medieval site known as the Mound of Down. This may have been the royal fortress of Niall, King of Ulaid, between 1016 and 1063.
Circling around the ditch to the right, you will find a set of modern steps leading up to a large oval enclosure. Within this at the far end you will see a Norman motte with a massive ditch around it, probably built by John de Courcy when he captured Downpatrick in 1177.
On a good day, there are fine views of the Cathedral and the Mountains of Mourne.
For the next point of interest, if you return to the road and turn left you will see a large stone gateway on your left.