St Harmon (Welsh: Llanarmon) is a village in Radnorshire, Powys, Wales. The population of the community at the 2011 census was 593. It is located on the Afon Marteg on the B4518 road running between Llanidloes and Rhayader. The parish church is called Saint Garmon,(Germanus of Auxerre), with many people assuming it has been spelt incorrectly. The community includes the settlement of Pantydwr.
St Harmon FC is the village football team. The Sun Inn was the village pub but has now been converted to a home.
- "Community population 2011". Retrieved 14 November 2015.