The Afon Erch is a short river on the

Llŷn peninsula The Llŷn Peninsula ( or , ) is a peninsula in Gwynedd, Wales, with an area of about , and a population of at least 20,000. It extends into the Irish Sea, and its southern coast is the northern boundary of the Tremadog Bay inlet of Cardigan Ba ...

Gwynedd Gwynedd () is a county in the north-west of Wales. It borders Anglesey across the Menai Strait to the north, Conwy, Denbighshire, and Powys to the east, Ceredigion over the Dyfi estuary to the south, and the Irish Sea to the west. The ci ...

Wales Wales ( ) is a Countries of the United Kingdom, country that is part of the United Kingdom. It is bordered by the Irish Sea to the north and west, England to the England–Wales border, east, the Bristol Channel to the south, and the Celtic ...

. It arises near the village of

Llanaelhaearn Llanaelhaearn is a village on the Llŷn Peninsula in the Local government in Wales, county of Gwynedd, Wales. Located in the community of (prior to 2024 called just "Llanaelhaearn") which also includes the larger village of Trefor, Gwynedd, Tr ...

, flowing south and southwest towards the hamlet of Llwyndyrys where it turns abruptly eastwards and curves around to the south, passing to the east of Y Ffor at Rhyd-y-gwystl. It continues towarin a SSW direction towards

Abererch Aber-erch (, Welsh for "Mouth of the Erch") is a small village and former civil parish on the Llŷn Peninsula in the Welsh county of Gwynedd. The village lies approximately east of Pwllheli. A river, the Afon Erch runs through the village. ...

where despite the village name, it does not enter the sea but flows west parallel to the coast for 1 mile to

Pwllheli Pwllheli ( ; ) is a market town and community on the Llŷn Peninsula (), in Gwynedd, north-west Wales. It had a population of 4,076 in 2011, which declined slightly to 3,947 in 2021; a large proportion (81%) were Welsh language, Welsh speaking. ...

. The Afon Rhyd-hir (translates from

Welsh Welsh may refer to: Related to Wales * Welsh, of or about Wales * Welsh language, spoken in Wales * Welsh people, an ethnic group native to Wales Places * Welsh, Arkansas, U.S. * Welsh, Louisiana, U.S. * Welsh, Ohio, U.S. * Welsh Basin, during t ...

as 'river of the long ford') joins the Afon Erch within the tidal basin of Pwllheli Harbour. Its headwaters gather to the south of

Llithfaen Llithfaen () is a village on the North West of Wales on the Llŷn Peninsula in Gwynedd, Wales. It is within the community of Pistyll near Caernarfon Bay. Pwllheli is the nearest town, approximately away, and Caernarfon is away. There is a sho ...

and flow south past

Llannor Llannor () is a village, parish and community located on the Llŷn Peninsula ( Welsh: ''Penrhyn Llŷn'') in the Welsh county of Gwynedd. Historically in Caernarfonshire, it lies 1.7 miles (2.8 km) north of Pwllheli and 18.0 miles (29.0 ...

to approach Pwllheli from the west. It is joined by the Afon Penrhos immediately west of the town, having originated around the extensive

bog A bog or bogland is a wetland that accumulates peat as a deposit of dead plant materials often mosses, typically sphagnum moss. It is one of the four main types of wetlands. Other names for bogs include mire, mosses, quagmire, and musk ...

of Cors Geirch, a national nature reserve. Parts of the courses of each of these rivers occupy valleys that were formed by glacial meltwater. The uppermost Penrhos is a

misfit stream A misfit stream is a river that is either too large or too small to have eroded the valley or cave passage in which it flows. This term is also used for a stream or river with meanders that obviously are not proportional in size to the meanders ...

within its valley. The name of the Erch either signifies 'dappled/dark' or is possibly a personal name. Until the 16th century Aber-erch did sit at the point at which the river entered the sea but the

longshore drift Longshore drift from longshore current is a geological process that consists of the transportation of sediments (clay, silt, pebbles, sand, shingle, shells) along a coast parallel to the shoreline, which is dependent on the angle of incoming w ...

of the sands of Morfa Abererch diverted it west thereafter.

References

{{coord, 52.89077, -4.40750, format=dms, type:river_region:GB, display=title Rivers of Gwynedd