The River Finn is a river in the west of Ulster, the northern province in Ireland. The river mainly flows through County Donegal, part of the Republic of Ireland, while a short stretch of the river also partially flows through County Tyrone, part of Northern Ireland. From Lough Finn, the river goes to Ballybofey and Stranorlar before joining the River Mourne at Lifford and Strabane.

County Donegal is a county of Ireland in the province of Ulster and in the Northern and Western Region. It is named after the town of Donegal in the south of the county. It has also been known as County Tyrconnell or Tirconaill, after the historic territory. Donegal County Council is the local council and Lifford is the county town.