Introduction
Blue Lough, Loch Gorm in Irish, takes its name from a trick of the light: the dark, peaty water reads vivid blue under a clear sky and turns close to black under cloud, changing through the day and the seasons. It sits in a glacial corrie in the Annalong Valley of the Mourne Mountains, County Down, wedged between the rocky slopes of Slieve Lamagan and the eastern wall of Slieve Binnian.
What sets it apart from the other high Mourne lakes is how little effort it takes to reach. If you want one short walk that delivers proper mountain scenery without a summit slog, this is the one to pick, and it’s worth carrying swimming kit, because the lough at the end is the point. It works as a family outing and as a cooling-off stop for hardened hikers coming down off the tors alike.
One thing to check first: major wildfires swept the Mournes in late April 2026, burning more than 1,000 hectares of heath and closing trails across the range, Blue Lough among them. By the time you read this the paths may well be open again, but it’s worth a look at the Northern Ireland Fire and Rescue Service site (nifrs.org) or local notices before you set out.
The Walking Route to Blue Lough
The direct route to Blue Lough is a straightforward out-and-back walk that follows well-established paths and historic tracks. It is a highly rewarding hike that packs impressive mountain vistas into a relatively short distance.
Starting the Journey
The walk begins at the Carrick Little car park on the Head Road, just outside the coastal village of Annalong. From the trailhead, a clear, stony track leads north into the mountains, rising at a gentle gradient between traditional dry-stone boulder walls. These impressive walls frame the lower fields and offer a glimpse of the rugged peaks rising at the head of the valley.
Crossing the Mourne Wall
After walking a short distance, the trail reaches a stone step stile positioned next to an iron gate. Here, you cross the famous Mourne Wall – a 22-mile stone monument that snakes over fifteen of the Mourne summits. At this point, the wall is descending from the high slopes of Slieve Binnian to the west before continuing east toward Long Seefin. Cross the wall at a right angle and follow the level track as it skirts the northern edge of Annalong Wood.
Granite Quarry Tracks and Percy Bysshe
Beyond the forest, the path transitions onto old quarry tracks that wind through open, heather-clad heathland. Historically, these routes were used by local stonecutters, and sections of the path remain paved with the original granite slabs. Look closely along the trail edges to spot evidence of historic stone working.
There are two main track junctions on this stretch; keep left at both to stay on course for the lough. Just before arriving, the path crosses a fast-flowing stream that drains out of the lake, and the Lamagan Slabs rear up on one side with Slieve Binnian on the other.
Trail Metrics
| Metric | Details |
|---|---|
| Distance | About 5 miles (8 km) return; some sources cite 3 miles for a shorter line |
| Typical Time | 2 to 2.5 hours |
| Difficulty | Easy to Moderate (gentle gradients but uneven underfoot) |
| Terrain | Stony quarry tracks, open heathland, and shallow stream crossings |
| Start/Finish | Carrick Little Car Park (Grid Ref: J345219) |
Wild Swimming in the Mournes
The dark, peaty water of Blue Lough is one of the better-known wild swims in Northern Ireland. Purple heather and tufts of white bog cotton ring the banks, and on a still day the water holds a clean reflection of the Lamagan Slabs and the North Tor of Slieve Binnian.
The lake is a popular spot for a refreshing dip, particularly for hikers descending from a strenuous walk along the high granite tors of Slieve Binnian. Accessing the water requires carefully picking your way through the shallow, stony deposits at the water’s edge before dropping into the deep, cool water.
Because the lough is fed by cold mountain run-off, the water temperature remains low throughout the year. Swimmers should enter slowly to prevent cold-water shock and ensure they have warm, windproof layers ready immediately upon exiting. The grassy, heather-lined banks surrounding the water provide a comfortable space to dry off and enjoy a picnic.
Extended Hiking Options
For walkers looking to extend their journey beyond the lough, the area serves as a gateway to more challenging mountain routes:
- The Ben Crom Col: Continue past Blue Lough along the main track for another 600 metres to reach the saddle (col) between Slieve Binnian and Slieve Lamagan. This high pass offers a spectacular, bird’s-eye view down onto the Ben Crom Reservoir and the deep valley below.
- The Slieve Binnian Circular Loop: Experienced hikers can incorporate the lough into a challenging 7-mile (11.2 km) loop. This route follows the Mourne Wall steeply up the rugged slopes of Slieve Binnian (747m) to its summit, traverses the dramatic Back Castles and North Tor, and then descends to the col to join the path past Blue Lough back to Carrick Little.
Practical Information
Getting There and Parking
The walk starts at the Carrick Little car park, located at the junction of the Head Road and Oldtown Road near Annalong. There are two gravel parking areas at the trailhead, privately managed on an honesty-box system; expect to pay a few pounds for the day, with recent visitors reporting around £3. Bring coins. The areas fill rapidly on sunny weekends and bank holidays, so arriving before 9am is the single best piece of planning here.
Facilities
There are no public toilets, changing areas, or shelters at Blue Lough or the Carrick Little trailhead. The nearest public facilities, convenience shops, and cafes are located in Annalong village, roughly 5 km down the road.
What to Wear and Pack
The trail is rocky in places and involves crossing small streams. Sturdy hiking boots with reliable ankle support are essential; standard trainers will easily get soaked and do not offer enough grip on the loose stones. Upland weather in the Mournes is notoriously unpredictable, so pack windproof layers, waterproofs, dry clothes for after a swim, and plenty of water.
Land Access and Etiquette
While the track to Blue Lough is a popular route, the land below 180 metres elevation is privately owned and actively farmed for grazing livestock. Visitors must respect local landowners by keeping dogs on a lead, closing all gates, and strictly adhering to Leave No Trace principles.
After completing your walk, take the short ten-minute drive down to Annalong Harbour to see the historic stone cornmill and enjoy a warm drink by the coast.