Moelwynion in the context of Moelwyn Mawr

Snowdonia, or Eryri (Welsh: [ɛrəri] ), 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 (Yr Wyddfa), 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 lower Moelwynion and Moel Hebog ranges lie immediately to the south.

The national park has an area of 823 square miles (2,130 km) (the fourth-largest in the UK), and covers most of central and southern Gwynedd and the western part of Conwy County Borough. This is much larger than the area traditionally considered Snowdonia, and in addition to the five ranges above includes the Rhinogydd, Cadair Idris, and Aran ranges and the Dyfi Hills. It also includes most of the coast between Porthmadog and Aberdyfi. The park was the first of the three national parks of Wales to be designated, in October 1951, and the third in the UK after the Peak District and Lake District, which were established in April and May 1951 respectively. The park received 3.89 million visitors in 2015.

The Snowdon Massif, Snowdon Range, or Yr Wyddfa massif, is one of the three mountain groups in Snowdonia (Eryri), north Wales, to include mountains over 3,000 feet (914 m) high. It occupies the area between Beddgelert, Pen-y-Pass and Llanberis. It is surrounded by the Glyderau to the north-east, Moel Siabod to the east, the Moelwynion to the south, Moel Hebog, the Nantlle Ridge and Mynydd Mawr to the west, and by flatter land leading down to Caernarfon and the Menai Strait to the north-west.

The Snowdon Horseshoe is the name given to the semi-circular ring of ridges and peaks on Snowdon's (Yr Wyddfa) eastern side, i.e. facing down Dyffryn Mymbyr towards Capel Curig. The peaks in the Horseshoe are those of Y Lliwedd, Snowdon, Garnedd Ugain and Crib Goch.