Llanfyllin is a market town and community in Powys, Wales. The community population in 2021 was 1,586 and the town's name mean…Llanfyllin is a market town and community in Powys, Wales. The community population in 2021 was 1,586 and the town's name means church or parish (llan) of St Myllin. The community includes the settlements of Bodfach, Ty Crwyn, Abernaint and several farms.