[[Image:The chapel in Llanarmon Mynydd Mawr - geograph.org.uk - 1050249.jpg|thumb|240px|St Garmon's church in Llanarmon Mynydd Mawr.]]
'''Llanarmon Mynydd Mawr''', occasionally referred to as Llanarmon Fach, is an isolated rural parish in [[Powys]], [[Wales]]. It was formerly in [[Denbighshire (historic)|Denbighshire]], and from 1974-1996 was in the county of [[Clwyd]]. It measures
The scattered settlement lies on the south-facing slopes of the [[Berwyn Mountains]] in the high upper part of the [[River Tanat|Tanat]] Valley, at around 950 feet above sea level. Its name translates roughly as "St Garmon's church [on the] Great Mountain", distinguishing it from the village of [[Llanarmon Dyffryn Ceiriog]], 5 miles away in the [[Ceiriog Valley]].