Little remains of the structures that once stood on the hill.
Such remains as are visible today, including three series of ramparts and other walls and some foundations, mostly date to the Middle Ages.
Archaeologist H. N. Savory described the fortifications as consisting of stone walls between 2.5 and 3 metres (8 and 10 ft) thick, which exploited every irregularity in the rocky hill-top, enclosing an irregular area of about a 10,000 m² (110,000 sq ft) in size.
The original means of access was by a steep path on the western side of the hillfort.
The present entrance from the north-east is a later addition.

Excavations in 1910 and 1954–56 revealed several periods of habitation at the site.
The earliest elements date to the Iron Age, perhaps to the 1st or 2nd century.
A pool within the enclosure, thought to be an artificial construction, may date to this phase.
It is perhaps connected to the pool found in the popular tale of Vortigern and the dragons.
Other traces suggest habitation into the 5th century, which would put it in the time frame for Vortigern and Ambrosius Aurelianus.

It has long been known that there is a pool inside the fort, but when the archaeologist Dr H. N. Savory excavated the hillfort between 1954 and 1956, he was surprised to find that not only were the fortifications of about the right time frame for either Vortigern or Ambrosius, but that there was a platform above the pool as described in the Historia Britonum.
However, he found the platform to date much later than the accepted floruit of either personage.
Little remains of the structures that once stood on the hill. Such remains as are visible today, including three series of ramparts and other walls and some foundations, mostly date to the Middle Ages. Archaeologist H. N. Savory described the fortifications as consisting of stone walls between 2.5 and 3 metres (8 and 10 ft) thick, which exploited every irregularity in the rocky hill-top, enclosing an irregular area of about a 10,000 m² (110,000 sq ft) in size. The original means of access was by a steep path on the western side of the hillfort. The present entrance from the north-east is a later addition.
Excavations in 1910 and 1954–56 revealed several periods of habitation at the site. The earliest elements date to the Iron Age, perhaps to the 1st or 2nd century. A pool within the enclosure, thought to be an artificial construction, may date to this phase. It is perhaps connected to the pool found in the popular tale of Vortigern and the dragons. Other traces suggest habitation into the 5th century, which would put it in the time frame for Vortigern and Ambrosius Aurelianus.
It has long been known that there is a pool inside the fort, but when the archaeologist Dr H. N. Savory excavated the hillfort between 1954 and 1956, he was surprised to find that not only were the fortifications of about the right time frame for either Vortigern or Ambrosius, but that there was a platform above the pool as described in the Historia Britonum. However, he found the platform to date much later than the accepted floruit of either personage.
Dinas Emrys