Mourne Wall

Wikipedia contributors · CC BY-SA · EN · 04/10/2026

The Mourne Wall was constructed to enclose a catchment area of the Silent Valley Reservoir in the Mourne Mountains, Northern Ireland. The 1.5 m high stone wall, which was built to keep livestock from contaminating water supplies, took almost twenty years to complete (1904 to 1922). The project was overseen by the Belfast City and District Water Commissioners.

History

Planning

Luke Livingston Macassey (1843–1908), an Irish civil engineer and barrister, was in 1874 appointed consultant hydraulic engineer by the Belfast and District Water Commissioners. The Commission had been set up in 1840 to ensure the water supply for Belfast, at that time an expanding city. In 1891 Macassey advised the construction of a reservoir in the Mourne Mountains, as a long-term solution.

The project required the acquisition of wayleaves and water rights. Private Acts of Parliament were passed, of 1893, 1897 and 1899, on behalf of the Commissioners.

The Silent Valley Reservoir was built between 1923 and 1933 to hold the water from the catchment area enclosed by the wall. The reservoir supplies Belfast via the Mourne Conduit/Aquarius pipeline. The main purpose of the Mourne Wall was to isolate the catchment area from cattle and sheep.

Construction

The wall was built from natural granite stone using traditional dry stone walling techniques. On average the wall is about 1.5 m high and 0.8 to thick and is estimated to be 19.5 mi long. Stonemasons worked from March to mid-October for 18 years to build the wall.

Topography

As the wall was built to contain the catchment area of the Mourne, the wall passes over fifteen of the highest mountains in the area (listed clockwise from the Kilkeel River):

Slievenaglogh 445 m

Slieve Muck 674 m

Carn Mountain 587 m

Slieve Loughshannagh 619 m

Slieve Meelbeg 708 m

Slieve Meelmore 680 m

Slieve Bearnagh 739 m

Slievenaglogh 586 m

Slieve Corragh 641 m

Slieve Commedagh 765 m

Slieve Donard 850 m

Rocky Mountain 525 m

Slieve Binnian 747 m

Wee Binnian 460 m

Moolieve 332 m

Management

The wall is maintained and owned by Northern Ireland Water.

Hiking

The Mourne Wall Challenge Walk is a challenging walking route following the historic Mourne Wall over seven of the ten highest mountains in Northern Ireland. In 2013, an event's designated route was recorded by a participant as being 30.51 km with a total 2527 m elevation, although the designated route of this event contained two significant diversions from the wall itself in the Silent Valley and Annalong Valley.

Different versions of Mourne Wall challenge routes have been posted on the internet in recent years. The first of these follows the entire length of the wall as a full circuit of the mountain land owned by Northern Ireland Water (including Silent Valley Mountain Park). A second version follows the perimeter of the rainfall catchment area only, cutting across the dam wall of the Silent Valley reservoir. A third version of the route was specified for an organised walking event in 2013. This version also appears in Paddy Dillon's guidebook 'The Mournes Walks'.

Source and attribution

Adapted from “Mourne Wall” by English Wikipedia contributors. Main paragraphs and sections are retained; tables, reference markers and technical markup are omitted. This is an encyclopedic adaptation, not a personal review. Original revision and contributor history ↗. Text is shared under CC BY-SA 4.0 ↗. Check current visitor access, tickets and transport with the relevant operator.