seaport and market town, County Donegal, Ireland, on the River Eske at the head of Donegal Bay. It is famed for its historic associations and picturesque environs. South of the town are the ruins of the Franciscan Donegal Abbey (founded 1474). Donegal Castle, a stronghold of the O'Donnells, was rebuilt in the early 17th century. The town is noted for its handwoven tweed. Pop. (2002) 2,453.

Donegal's population is concentrated largely along the coasts and river valleys; the main towns are Donegal, Buncrana, Ballyshannon, and Letterkenny. With the exception of the county's urban districts, Donegal is administered by a county council and county manager. The Foyle and Finn basins are intensively cultivated, but the rugged western seaboard is unsuitable for cultivation. Agriculture consists of tillage and the rearing of cattle, sheep, and poultry; the chief crops are oats and potatoes. Killybegs on the southwest coast is the main fishing port and a fish-processing centre. Salmon are caught in the Rivers Finn, Foyle, Erne, and Gweebarra. Owing to the county's scenery and its many beaches and golf courses, tourism is important. In west Donegal, which remains an Irish-speaking region, woolen garments are made by hand, and, at Convoy, Donegal tweeds are woven. The county also has light industry. Modern railway lines no longer serve Donegal, though railway enthusiasts in the county maintain a railway heritage centre.

The name Donegal was extended from the town to the county, which was made a shire in 1585. The ancient name was Tyrconnell (“Land of Conall”). Conall, with his brother Eoghan, conquered northwestern Ulster in approximately 400 and founded the kingdom of Ailech; its capital was at the concentric stone fortress known as the Grianan of Ailech on a hill west of Londonderry, Northern Ireland. Eoghan took Tyrone and Inishowen for his share, and his descendants, the O'Neills, ruled central Ulster. Conall took Tyrconnell, which his descendants, the O'Donnells, ruled. The remoteness of these areas enabled them to escape serious interference from the Anglo-Normans. Following the defeat of the Irish cause in 1603, however, Hugh O'Neill (O'Neill, Hugh) and Rory O'Donnell (Tyrconnell, Rory O'Donnell, 1st Earl of, Baron Of Donegall) took flight secretly to the European continent in 1607. The county was immediately included in the plan for the plantation of Ulster, and its history thereafter merged with that of Ireland. Area 1,877 square miles (4,861 square km). Pop. (2002) 137,575; (2006) 147,264.