River Gwyrfai
General data
- Name: River Gwyrfai
- Water system: Irish Sea
- Water type: River
- Progression: Menai Strait -> Irish Sea -> Atlantic Ocean -> Planet Earth
- Climates: Temperate
- Continents: Europe
- Countries: Wales (UK)
Afon Gwyrfai is a short river in Gwynedd, Wales, flowing for half of its length through Snowdonia National Park. Exiting Llyn y Gader it flows north through the small village of Rhyd-ddu to enter the southeastern end of Llyn Cwellyn. Downstream of the lake it flows northwest past Betws Garmon, leaving the national park and continues to the southern edge of Waunfawr. It then turns slightly west to flow on to Bontnewydd beyond which it turns slightly south to enter Foryd Bay (Y Foryd). The tidal channel within the bay flows north into the western end of the Menai Strait.