Ystradfellte - Wikipedia. Ystradfellte is a small village and community in southern Powys, Wales belongs to the historic county of Brecknockshire (Breconshire) and the Fforest Fawr area of the Brecon Beacons National Park lies beside the Afon Mellte.The village is linked by minor roads with Heol Senni to the north and the A4059 north of Penderyn, and with Pontneddfechan at …