page_title: County Donegal
section_title: Physical geography
hierarchical_section_title: County Donegal / Geography and political subdivisions / Physical geography
context_page_description: County Donegal is a county of Ireland in the province of Ulster. It is named after the town of Donegal in the south of the county. It has also been known as County Tyrconnell, after the historic territory of the same name, on which it was based. Donegal County Council is the local council and Lifford the county town.
  The population was 159,192 at the 2016 census.
context_section_description: The county is the most mountainous in Ulster consisting chiefly of two ranges of low mountains; the Derryveagh Mountains in the north and the Blue Stack Mountains in the south, with Errigal at 749 metres (2,457 ft) the highest peak. It has a deeply indented coastline forming natural sea loughs, of which both Lough Swilly and Lough Foyle are the most notable. The Slieve League cliffs are the sixth-highest sea cliffs in Europe, while Malin Head is the most northerly point on the island of Ireland.
  The climate is temperate and dominated by the Gulf Stream, with warm, damp summers and mild wet winters. Two permanently inhabited islands, Arranmore and Tory Island, lie off the coast, along with a large number of islands with only transient inhabitants. Ireland's second longest river, the Erne, enters Donegal Bay near the town of Ballyshannon. The River Erne, along with other Donegal waterways, has been dammed to produce hydroelectric power. The River Foyle separates part of County Donegal from parts of both counties Londonderry and Tyrone.
caption: Glengesh Pass, near Ardara
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