Aran Fawddwy is a mountain in southern Snowdonia, Wales, United Kingdom. It is the highest point of the historic county of Merionethshire. It is the highest peak in the Aran mountain range, the only peak in Wales outside North Snowdonia above 900m, and higher than anywhere in the United Kingdom outside Northern Snowdonia, the Scottish Highlands and the Lake District. The nearest small settlements to the mountain are Dinas Mawddwy to the south, Llanymawddwy to the southeast, Llanuwchllyn on the shores of Bala Lake to the north, and Rhydymain to the west. The nearest settlements with around 2,000 people are Bala and Dolgellau. On the eastern slopes of Aran Fawddwy is the small lake named Creiglyn Dyfi, the source of the River Dyfi. Its sister peak is Aran Benllyn at 885 metres (2,904 ft). There is also a middle peak: Erw y Ddafad-ddu.

Snowdonia, or Eryri, is a mountainous region and national park in North Wales. It contains all 15 mountains in Wales over 3000 feet high, including the country's highest, Snowdon, which is 1,085 metres (3,560 ft) tall. These peaks are all part of the Snowdon, Glyderau, and Carneddau ranges in the north of the region. The shorter Moelwynion and Moel Hebog ranges lie immediately to the south.