[5][6] The Mourne Wall crosses fifteen of the summits and was built to enclose the catchment basin of the Silent Valley and Ben Crom reservoirs.

[7][8] The older name of this mountainous territory was Bairrche, which is likely a collective noun derived from the Irish barr, meaning 'top, peak'.

[34] This followed a number of Acts of Parliament allowing the sale, and the establishment of a water supply from the Mournes to the growing industrial city of Belfast.

[36] Tollymore Forest Park is at Bryansford, near the town of Newcastle in the Mourne and Slieve Croob Area of Outstanding Natural Beauty.

The river is a spawning ground for salmon and trout and is an Area of Special Scientific Interest for its geology, flora and fauna.

Other plants which grow in the area are: common cottongrass, roseroot, harebell, marsh St John's-wort, wild thyme, wood sorrel and heath spotted orchid.

Sheep graze high into the mountains, and the range is also home to birds, including the raven, peregrine falcon, wren, buzzard, meadow pipit, grey wagtail, stonechat and snipe.

"Discover Northern Ireland", a website operated by Tourism NI, promotes the Mourne Mountains as a popular destination for hiking and taking in views of the surrounding landscape, including local forests and the coastline.

[43] Two-thirds of all visitors made a single-day trip rather staying overnight, and party sizes averaged between 3 and 4 people.

[44] There are many granite cliffs, in the form of outcrops and tors, scattered throughout the range, making the Mournes one of Northern Ireland's major rock-climbing areas since the first recorded ascents in the 1930s.

[48][49] The plan has been subject to controversy because of the area's status as private property, with over 1,000 farmers based in the proposed park,[49] and also because of fears over the impact on local communities, bureaucracy and house prices.

[53] In the 1950s, Emyr Estyn Evans had written that some shepherds in the Mournes tended to burn gorse and heather recklessly.

[54] In the 21st century there have been hundreds of heather and gorse wildfires in the Mournes each year, the vast majority started deliberately, with "farmers and vandals" often blamed.

[55] It is claimed many of the wildfires are caused by hill farmers and landowners carrying out unapproved burning to clear gorse/heather and thus maximize the subsidy payments they receive for the amount of grazing-land they have.

[56] In April 2021, more than a hundred firefighters tackled a major gorse wildfire in the eastern Mournes, which blazed for three days and devastated habitat in the area.

"The Mountains of Mourne" are also mentioned in John Lennon's song "The Luck of the Irish" on the album Some Time in New York City.

[61] The scenery of the Mourne Mountains have also provided the backdrop for a number of productions, most famously HBO's Game of Thrones.

[63][64] The Mourne Mountains also influenced C. S. Lewis to create the mythical world featured in his The Chronicles of Narnia series.