Llanddewi Ystradenni is a community in Radnorshire, Powys, Wales. The population of the Community at the 2011 census was 310.[1]
Centred on the village of Llanddewi, it also includes the hamlet of Heartsease.
The motte and bailey fortification of Buddugre Castle, overlooking the Afon Ithon, is also within the community.52°18′0″N 3°18′0″W / 52.30000°N 3.30000°W