Llanarmon Mynydd Mawr is a village in Powys, Wales.
It is situated within the SY10 postcode district, which is within the Oswestry post town.
The full list of postcode districts within the Oswestry post town is as follows:
The Oswestry post town is within the Shrewsbury postcode area.
Administrative Ward: Llanrhaeadr-ym-Mochnant/Llansilin
Administrative District: Powys
Country: Wales
UK Parliament: Montgomeryshire