Afon Meillionen is a small river

River

A river is a natural watercourse, usually freshwater, flowing towards an ocean, a lake, a sea, or another river. In a few cases, a river simply flows into the ground or dries up completely before reaching another body of water. Small rivers may also be called by several other names, including...

 near Beddgelert

Beddgelert

Beddgelert, or in older English spelling often Bedgellert, is a village and community in the Snowdonia area of Gwynedd, Wales. It is reputed to be named after the legendary hound Gelert. Population 617.- History:...

 in Gwynedd

Gwynedd

Gwynedd is a county in north-west Wales, named after the old Kingdom of Gwynedd. Although the second biggest in terms of geographical area, it is also one of the most sparsely populated...

, north-west Wales

Wales

Wales is a country that is part of the United Kingdom and the island of Great Britain, bordered by England to its east and the Atlantic Ocean and Irish Sea to its west. It has a population of three million, and a total area of 20,779 km²...

.

It flows down Cwm Meillionen, a small valley which lies on the north-eastern side of Moel yr Ogof

Moel Yr Ogof

Moel yr Ogof is a summit in Snowdonia. It is a subsidiary summit of Moel Hebog and a sister peak to the lower Moel Lefn.Owain Glyndwr's cave can be found on the cliff at the western flank of the mountain. The Beddgelert Forest lies directly to the north east, while Cwm Pennant lies to the west....

 (655m). Much of the river's catchment area lies within Beddgelert Forest.

Afon Meillionen is a tributary

Tributary

A tributary or affluent is a stream or river that flows into a main stem river or a lake. A tributary does not flow directly into a sea or ocean...

 of the Afon Colwyn

River Colwyn

The River Colwyn is a small river in Gwynedd, north-west Wales, a tributary of the River Glaslyn....

, which itself joins the Afon Glaslyn

River Glaslyn

The Afon Glaslyn is a river in Gwynedd, north-west Wales. Whilst not of great significance in terms of its length , it is one of Gwynedd's primary rivers, and has greatly influenced the landscape in which it flows....

 in the village of Beddgelert.

"Meillionen" is also the name of a farmhouse in the Cwm and of a small halt on the Welsh Highland Railway

Welsh Highland Railway

The Welsh Highland Railway is a long restored narrow gauge heritage railway in North Wales, operating from Caernarfon to Porthmadog, and passing through a number of popular tourist destinations including Beddgelert and the Aberglaslyn Pass. At Porthmadog it connects with the Ffestiniog Railway...

 between Caernarvon and Porthmadog

Porthmadog

Porthmadog , known locally as "Port", and historically rendered into English as Portmadoc, is a small coastal town and community in the Eifionydd area of Gwynedd, in Wales. Prior to the Local Government Act 1972 it was in the administrative county of Caernarfonshire. The town lies east of...

.