BALLYSHANNON, town, Co. Donegal, Ireland, at the mouth of the Erne ; on the Bundoran branch of the Great North ern railway. Pop. (1926) 2,112. The river is here crossed by a bridge which connects the town with the suburb of The Port. Below the bridge the river forms a cascade, where salmon are trapped in large numbers. The fisheries are of great value, and there is an export trade to England in salmon. The harbour is a small exposed creek of Donegal bay, and is only accessible to small vessels owing to a bar. Previous to the Union Ballyshannon returned two members to the Irish parliament and it was incor porated by James I. There are slight remains of a castle of the O'Donnells, earls of Tyrconnell, where the English were defeated in 1597. There are numerous raths or encampments in the vicinity and other remains. Coolmore, 3m. north-west, is a bathing-resort.