River Clywedog
General data
- Name: River Clywedog
- Water system: River Severn
- Water type: River
- Progression: River Severn -> Severn Estuary -> Bristol Channel -> Celtic Sea -> Atlantic Ocean -> Planet Earth
- Climates: Temperate
- Continents: Europe
- Countries: England (UK), Wales (UK)
The Afon Clywedog is an upland headwater tributary of the River Severn in Powys, Wales. It is approximately 29 km (18 mi) long and has its source on the flanks of Plynlimon and has its confluence with the Severn in Llanidloes. The annual rainfall over the catchment is between 1,737 mm (68.4 in) and 1,836 mm (72.3 in).