The Mourne Mountains, usually just referred to as "The Mournes", are the highest peaks of Northern Ireland. They are dramatic and form the background to the south of County Down. Closer to Newcastle they are brooding giants. Along the coast south of Annalong their loose stones have been painstakingly shifted to form a tapestry of small fields with drystone walls.
In April 2021 the Mournes suffered a wildfire centred on Slieve Donard. It will be an unpleasant charred mess for some months, with charcoal pencils of heather scratching your trousers and shins, until new growth takes over.
The Mourne Mountains were formed by volcanic activity 66 million years ago in the Mesozoic Era. This activity didn't break surface as erupting volcanoes, so you don't see spiky peaks or basalt columns; rather it was an upwelling of magma beneath the Silurian sandstone, shale and mudstone that cloaks County Down further north. Glaciers during several Ice Ages wore away the upper layers until the granite was exposed - this is very hard-wearing so the Mournes weathered less than other Irish mountain ranges, and have the highest peaks in Northern Ireland. The glaciers carved out the U-shaped Silent Valley and left vast boulders teetering on the slopes. Prehistoric dwellers used the stone for their sturdy monuments, exporting it as far as the Brú na Bóinne complex near Drogheda, and shifting it off their fields into drystone walls. The granite was quarried for building stone from prehistory to the present day. Further north around Slieve Croob is a very much older crop of granite, then in the lowlands towards Downpatrick are drumlins, hillocks of gravel deposited beneath the glaciers, forming islands where they meet the sea at Strangford Lough.
West of the Mournes is a long broad valley then the mountains of the Ring of Gullion, a collapsed volcanic caldera. It's probably older than the Mournes; it's arguably less scenic. To the south is Carlingford Lough, the only fjord on Ireland's east coast, separating County Down from the Republic. Those areas are described under Newry and aren't considered further here.
The mountains draw the cloud and rain, so the peaks get 2000 mm annual rainfall, while the coast averages 1300 mm and Murlough is in a "rain shadow" with only 750 mm. The terrain is therefore distinctly soggy, and reservoirs catch the rainfall for Belfast's water supply. Potatoes are grown on the low ground, cattle graze the grassy gentler slopes, and sheep munch away right up to the summits, wherever they're not impeded by the Mourne Wall. The highest peaks, clad in heather and gorse, are towards Newcastle: Slieve Donard is highest at 850 m but most of the Mournes are in the 500-650 m range, with some 70 lesser hills of 300-400 m. So they're a good Saturday afternoon hike but don't demand technical mountaineering, and they're also very accessible from the cities.
They were not always so accessible: they were spoken of as an island, which they look like from afar, and until the road around the coast was built in the 19th century, you could only reach places such as Kilkeel and Annalong by boat. The villages had fishing fleets, and shipped out granite to pave the streets of Victorian Britain. So much for the legitimate trade - the Brandy Pad trail was a mountain route for contraband, and perhaps for a few wanted men. Defeated Jacobites after the Battle of the Boyne laid low in the hills and practised small-scale resistance, until the militias and courtrooms at Banbridge crushed them.
There is still quarrying and gravel extraction in the area but it's small scale, and the main industries are farming, forestry, fishing, and of course tourism. Thus, it's a managed, farmed, inhabited landscape and not a wilderness. In 1966 the Mournes were designated as an Area of Outstanding Natural Beauty (AONB), and in 1986 this was extended to include Slieve Croob and the nearby farmlands and coastline. (It doesn't include Ring of Gullion or Strangford Lough, which are separately designated.) Carlingford Lough is a RAMSAR site, Murlough and Rostrevor Wood are National Nature Reserves, and there are many SSSIs - sites of special scientific interest. The National Trust owns large tracts of the Mournes. There were moves in the early 21st century to designate the area as a National Park, but this was rebuffed by residents and local councillors who feared ceding control to a distant, less democratic body. One problem had been the multiple local authorities with a stake in the area, but this was resolved by the reorganisation of 2015 which brought the whole area within Newry, Mourne and Down District. There are no park fees, permits or gates to enter the Mournes, you simply pay for individual amenities such as parking.
There are regular buses from Belfast Europa station to Newcastle, and to Newry continuing to Dublin airport and city. The Belfast-Dublin trains also stop in Newry.
A less frequent bus runs cross-country from Newry to Newcastle and Downpatrick.
An hourly bus runs from Newry to Warrenpoint, Rostrevor and Kilkeel, and another bus runs every couple of hours between Kilkeel and Newcastle. On M, W, F a bus makes two runs from Kilkeel up to Attical at the entrance to Silent Valley.
So it is possible to reach all the area's towns by public transport, and to circle the mountains, but altogether it's much easier by car. (On fine weekends, what feels like half the population of Belfast will drive here to demonstrate this point.) You'll also need a car to reach the start of the various hikes.
Carlingford Ferry 📍 plies across the opening of the lough between Greencastle in County Down and Greenore in the Republic east of Dundalk. See Newry#Get in for details.
You'll need a car. The Rambler bus no longer runs.
Standard advice on suitable clothing and footwear for the hills. But they're of no great altitude and your main hazard is road traffic.
The towns all have a mobile and 4G signal, but there are lots of dead areas beyond, even on the approach highways. Don't be relying on a mobile up in the hills.
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