The Mourne Mountains ( ; ), also called the Mournes or the Mountains of Mourne, are a predominantly granite mountain range in County Down in the south-east of Northern Ireland. They include the highest mountain in all of Ulster, Slieve Donard at . The Mournes are designated an Area of Outstanding Natural Beauty and it has been proposed to make the area Northern Ireland's first national park. The area is partly owned by the National Trust and sees over 50,000 visitors every year. The Mourne Wall crosses fifteen of the summits and was built to enclose the catchment basin of the Silent Valley and Ben Crom reservoirs. The wall, and the area inside it, are owned by Northern Ireland Water.
Name
The name 'Mourne' is derived from the name of a Gaelic clan or sept called the Múghdhorna. The older name of this mountainous territory was Bairrche, which is likely a collective noun derived from the Irish barr, meaning 'top, peak'. This survives in the Irish name for the mountains, Na Beanna Boirche, literally "the peaks of the peak district". It was historically anglicized as 'Bennyborfy'. The name Bairche or Boirche was also personified as the mythical shepherd of the mountains. While all Irish dialects and many Hiberno-English speakers pronounce this word with an sh sound, this is commonly dropped in English as spoken in the region and rarely reflected in anglicised spellings.
Mountains
right|thumb|300px|[[Mourne Wall|The Mourne Wall on Slieve Donard, looking west]]
thumb|300px|The eastern Mournes seen from Annalong Wood
On clear days, the Mourne Mountains can be seen from the Isle of Man and Dublin.
{| class="wikitable sortable" style="text-align:left"
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|+ style="text-align: left;" |Highest summits (MountainViews Online Database)
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!style="text-align:left"|Rank
!style="text-align:left"|Name
!style="text-align:left"|Irish name
!style="text-align:left"|Prominence