The Battle of Bryn Glas was a battle between the Welsh and English on 22 June 1402, near the towns of Knighton and Presteigne in Powys, Wales. It was part of the Glyndŵr Rising of 1400-1415. It was an important victory for the Welsh under Owain Glyndŵr, as it resulted in the prolongation of the Welsh war of independence and the destabilisation of English politics for several years afterward.

Knighton is a market town and community on the River Teme, straddling the border between Powys, Wales and Shropshire, England. It lies in the traditional county of Radnorshire. Originally an Anglo-Saxon settlement, Knighton is located on Offa's Dyke, the ancient earthwork that divided the two countries. It later became a Norman defensive border town.