Castell Bryn Gwyn (c) Bill Nicholls
Castell Bryn Gwyn

Castell Bryn Gwyn is one of a number of prehistoric sites in the fields near Brynsiencyn village. The 'castle' is a fortified enclosure, probably erected in the Neolithic period, though it appears to have been used throughout the Iron Age and the Roman period.


The first occupation at Bryn Gwyn appears to have been as early as 2500 BCE. Flint tools and pottery from the 3rd millennium have been found underneath the earthen walls that surround the site.

Castell Bryn Gwyn is sometimes called a hill fort, though that gives an erroneous idea of the site. It isn't a hill fort, but a defensive enclosure, built on low lying ground. However, the shape of the enclosure and the formation of the ditch and bank defences are similar to what you might find at a hill fort.

The banks are up to 10m wide and almost 5m high in places. The entire site was originally enclosed in a second, smaller ditch, of which nothing remains.

We know little about how the site was used, but one suggestion is that it was the site of a castle built by King Olaf, ancestor of Gruffudd ap Cynan.

A short walk away from the Castell site is Bryn Gwyn standing stones, the Neolithic Burial Chamber of Bodowyr, and the Caer Leb prehistoric enclosure.