River Derg

The River Derg is a small river in Ireland. The river has its source in the Lough Derg, in County Donegal, Republic of Ireland and it flows into County Tyrone, Northern Ireland east through Castlederg to join the River Strule forming the River Mourne. The upper reaches of the catchment are characterised by peatland, while the lower reaches flow predominantly through farmland.[1] The River Derg's length is 28 miles (45 km).[2]

River Derg
River Derg and the Ardstraw Bridge
Etymology	From Lough Derg, 'red lake'
Native name	Abhainn na Deirge
Location
Country	Republic of Ireland, Northern Ireland
Physical characteristics
Source
• location	Lough Derg, County Donegal, Republic of Ireland
• elevation	138 metres (453 ft)
Mouth
• location	North Channel via Lough Foyle, River Foyle, River Mourne
Length	45 kilometres (28 mi)
Basin size	440 square kilometres (170 sq mi)
Discharge
• average	16.2 m3/s (570 cu ft/s)

River Derg on the Northern Ireland side of the border

The River Derg is known for its salmon, grilse and sea trout.