Afon Glaslyn

Last updated

Glaslyn Gorge Aberglaslyn Pass.jpg
Glaslyn Gorge

The Afon Glaslyn (English, River Glaslyn) is a river in Gwynedd, north-west Wales. While not of great significance in terms of its length (about 16 miles (26 km)), it is one of Gwynedd's primary rivers, and has greatly influenced the landscape in which it flows.

It has its source in Glaslyn, a cirque lake on the flanks of Snowdon. It is joined by Nant Traswnant which drains Pen-y-Pass and by Nant Cynnyd before entering the beautiful lake, Llyn Gwynant. The river then flows through Llyn Dinas before entering the village of Beddgelert. In the middle of the village it is joined by the substantial tributary, the Afon Colwyn which drains the south western flank of Snowdon. The much enlarged river flows down past Gelert's grave before tumbling down into the Pass of Aberglaslyn. This is a small rocky gorge close to the main road which provides easy public access to a most picturesque piece of Snowdonian scenery.

Passing through Pont Aberglaslyn, the river emerges from the gorge into the relatively flat agricultural land of Tremadog and Porthmadog. This wide flat valley now called Traeth Mawr  was once the estuary of the Glaslyn before the Porthmadog Cob was created. This sealed off the mouth of the estuary enabling the land to be reclaimed. Once the river has crossed under the railway line, it meanders in large pools and marshes before eventually passing through the tidal sluices on the Cob at the south-eastern end of the town of Porthmadog, and from there into Tremadog Bay. Further south, the River Dwyryd also drains into Tremadog Bay.

The first pair of breeding ospreys in Wales nest at Pont Croesor about 4 miles (6.4 km) upstream from Porthmadog where the RSPB have set up observation facilities. [1] They first bred in 2005 and have returned every year since.

Fishing on the Glaslyn up to Beddgelert is controlled by the Glaslyn Angling Association.

Related Research Articles

Snowdonia Region in north Wales

Snowdonia is a mountainous region in northwestern Wales and a national park of 823 square miles (2,130 km2) in area. It was the first to be designated of the three national parks in Wales, in 1951. It contains the highest peaks in the United Kingdom outside of Scotland.

Beddgelert Human settlement in Wales

Beddgelert is a village and community in the Snowdonia area of Gwynedd, Wales. The population of the community taken at the 2011 census was 455. and includes Nantmor and Nant Gwynant. It is reputed to be named after the legendary hound Gelert. The community is large and sparsely populated and covers nearly 86 square kilometres.

Porthmadog Human settlement in Wales

Porthmadog, known before 1974 by its anglicised name of Portmadoc and locally as "Port", is a Welsh coastal town and community in the Eifionydd area of Gwynedd. Before the re-organisation of 1974 it was in the historic county of Caernarfonshire. It lies 5 miles (8 km) east of Criccieth, 11 miles (18 km) south-west of Blaenau Ffestiniog, 25 miles (40 km) north of Dolgellau and 20 miles (32 km) south of Caernarfon, with a community population of 4,185 and an estimated 4,107 in 2018. It developed in the 19th century as a port for slate sent to England and elsewhere, but since the decline of the industry it has become a shopping centre and tourist destination. It is close to Snowdonia National Park and the terminus of the Ffestiniog Railway. The 1987 National Eisteddfod was held in Porthmadog. It includes the nearby villages of Borth-y-Gest, Morfa Bychan and Tremadog.

Welsh Highland Railway heritage railway in the Welsh county of Gwynedd

The Welsh Highland Railway (WHR) or Rheilffordd Eryri is a 25-mile (40.2 km) long, restored 1 ft 11 12 in narrow gauge heritage railway in the Welsh county of Gwynedd, 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 and to the short Welsh Highland Heritage Railway. In Porthmadog it uses the United Kingdom's only mixed gauge flat rail crossing.

Glaslyn lake in Gwynedd, Wales

Glaslyn is a lake in the Snowdonia National Park in Gwynedd, north-west Wales.

River Dwyryd River in Gwynedd, Wales

The River Dwyryd is a river in Gwynedd, Wales which flows principally westwards; draining to the sea into Tremadog Bay, south of Porthmadog.

Traeth Mawr

Traeth Mawr is a polder near Porthmadog in Gwynedd in Wales. The area was formerly the large tidal estuary of the Afon Glaslyn. It was created after large-scale land reclamation occurred in the late 18th century and the early 19th century. A large embankment, called the Cob, separates the area from the sea and carries a road and railway line.

Croesor Tramway

The Croesor Tramway was a Welsh, 2 ft narrow gauge railway line built to carry slate from the Croesor slate mines to Porthmadog. It was built in 1864 without an Act of Parliament and was operated using horse power.

Afon Seiont is a river in Gwynedd, Wales which runs into the Menai Strait.

Llanberis Pass road

The Llanberis Pass in Snowdonia carries the main road (A4086) from the south-east to Llanberis, over Pen-y-Pass, between the mountain ranges of the Glyderau and the Snowdon massif. At the bottom of the pass is the small village of Nant Peris.

Llyn Cwellyn lake in the United Kingdom

Llyn Cwellyn is a reservoir in North Wales which supplies drinking water to parts of Gwynedd and Anglesey. It lies on the Afon Gwyrfai in Nant y Betws between Moel Eilio and Mynydd Mawr in the northern part of Snowdonia National Park. It has an area of 215 acres (0.87 km2), and is over 120 ft (37 m) deep. At the southern end is the small village of Rhyd Ddu.

Afon Colwyn River in Gwynedd, Wales

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

Nant Gwynant

Nant Gwynant is a valley in north Wales. The A498 road descends 600 feet (180 m) into the valley in about two miles from Pen-y-Gwryd; it follows the Nant Cynnyd, the Afon Glaslyn and alongside Llyn Gwynant, then beside the Nant Gwynant river to Llyn Dinas and passing below Dinas Emrys to Beddgelert. The road continues through the Aberglaslyn Pass to Porthmadog.

Aberglaslyn Pass mountain pass in Snowdonia, Wales

The Aberglaslyn Pass is a narrow gorge of considerable beauty in Snowdonia, Gwynedd, north Wales. The A498 road/A4085 road follows a relatively level route along the Afon Glaslyn through the pass from Beddgelert to Prenteg and then continues at the edge of the Traeth Mawr via Tremadog to Porthmadog.

A498 road

The A498 is a 16-mile road between Pen-y-Gwryd and Porthmadog in North Wales.

A4085 road

The A4085 is a 20-mile road between Caernarfon and Penrhyndeudraeth in North Wales that runs through the scenic Aberglaslyn Pass. There are several locations where the road is of substandard width.

Afon Meillionen River in Gwynedd, Wales

Afon Meillionen is a small river near Beddgelert in Gwynedd, north-west Wales.

Morfa Bychan Human settlement in Wales

Morfa Bychan is a village located in Gwynedd, North Wales.

Pont Aberglaslyn Grade II listed building in Gwynedd. Spanning the Afon Glaslyn approximately 1km W of Nantmor.

Pont Aberglaslyn is a bridge over the Afon Glaslyn and the surrounding hamlet, located near Beddgelert and Nantmor in Gwynedd, north-west Wales. A well-known beauty spot, according to Peter Bishop it was "one of the most visited sites in north Wales" at the end of the eighteenth century; an 1883 guidebook wrote that it "has occupied the artist's pencil perhaps more than any other".


  1. "Glaslyn Ospreys 2018 | Bywyd Gwyllt Glaslyn Wildlife" . Retrieved 5 February 2019.

Coordinates: 52°55′N4°07′W / 52.917°N 4.117°W / 52.917; -4.117