Hi,
I am researching in the area you are asking about. It is quite confusing as it is known
by several different names. It is mostly referred to as Llansanffraid Cwmteuddwr and is
on the outskirts of Rhayader (Rhaeadr) in Radnorshire which is now part of Powys. I
have seen it on records as Cwmdeuddwr and Cwmtoyddwr.
You will find on a roadmap that it is marked as Llansantffraed Cwmdeuddwr and is west of
Rhayader..
There are many researchers with ancestors in this area so good luck with your research.
Regards,
Margaret Harvey