Bronllys is a village and community situated in Powys, Wales, nestled between the towns of Brecon and Talgarth.

The castle was originally founded around 1100 by Richard Fitz Pons, the owner of the adjacent Herefordshire barony of Clifford, who was a supporter of Bernard of Neufmarché, the Lord of Brecknock (in which the land around Bronllys fell).

The castle initially featured a wooden structure typical of the motte-and-bailey design.

By the time it became a crown property in 1521, Bronllys Castle had fallen into significant disrepair, a fact recorded by the antiquarian John Leland.

Today, the castle is managed by Cadw, the organization responsible for preserving historic monuments in Wales, and it is open to the public between April and October.