The River Finn is a river that flows through County Donegal in the Republic of Ireland and County Tyrone in Northern Ireland. It rises in Lough Finn in County Donegal and flows east through a deep mountain valley to Ballybofey and Stranorlar (on opposite sides of the river) and on to the confluence with the River Mourne at Lifford. From Castlefin downstream the river is tidal, becoming deeper towards Strabane. The Finn is long and together with its tributary the Reelin River, drains a catchment area of 195 square miles. The River Foyle is formed by the confluence of the River Mourne and the River Finn, west of Lifford Bridge. The area which the River Finn flows through is called the Finn Valley. The village of Clady, near Strabane in County Tyrone, is on the River Finn. The football club in Ballybofey, Finn Harps, is named after the river.