BALLYSHANNON, a seaport and market-town of Ireland, county of Donegal, situated at the mouth of the Erne. Lat. 54° 30' N., long. 8° 11' W. The river is here crossed by a bridge of fourteen arches, which connects the town with the suburb of Purt. Below the bridge the river forms a beautiful cascade, 150 yards wide, with a fall at low water of 16 feet. The harbour is a small creek of Donegal Bay, about 600 yards long and 350 yards broad, and is only accessible to small vessels. The town contains a church, several chapels, a bank, a market-house, barracks, and a union workhouse. The salmon fishery is the only i mportant occupation. Previous to the Union Ballyshannon returned two members to the Irish Parliament. Population in 1871, 2958.