Blue Lough

Overview

Blue Lough is a small, peaty‑coloured lake tucked in the Annalong Valley of the Mourne Mountains. It lies between the imposing slopes of Slieve Binnian to the south‑west and Slieve Lamagan to the north‑east, with the striking Lamagan slabs framing its western edge. The lake’s clear water mirrors the sky, making it a favourite spot for walkers who want a quick, invigorating dip after a day on the trails.

History & Geology

The lake occupies a classic glacial corrie – a bowl‑shaped hollow carved by ice during the last Ice Age, roughly twelve thousand years ago. As the glacier retreated it left a steep granite back wall and a moraine dam at the eastern edge, allowing rain‑water and runoff to fill the basin. In Irish the lough is known as Loch Gorm, meaning “the blue lake”.

The water’s colour shifts dramatically with the weather: on a clear sunny day the lake appears a vivid blue, while overcast skies turn it a deep slate‑grey, and after heavy rain it can take on a greenish hue. These changes are caused by the lake’s depth (up to 14 m), the mineral‑rich granite surrounding it, and the angle of sunlight – no algae or dye is involved.

Walking Route

The most popular approach starts from Carrick Little car park on the Head Road above Annalong. From there the path follows the Annalong River upstream, crossing a small stream and the Mourne Wall before opening into the corrie.

Loop Options

Several walkers extend the out‑and‑back into a 9.6 km loop that returns to the car park via the opposite side of the valley (as described on HiiKER). The loop adds about 30 minutes of walking and offers a different perspective of the surrounding peaks.

Optional Extensions

• Summit Slieve Binnian – add 1.5–2 hours for a summit scramble and panoramic views.
• Ben Crom col – a short 600 m detour gives a bird’s‑eye view of Ben Crom Dam.
• Silent Valley Reservoir – continue past the col for a longer ridge walk linking to the Silent Valley area.

Seasonal Highlights

The lake’s colour is at its most striking on a clear day in late spring or early summer, when the surrounding heather is in full bloom. In early autumn the heather turns a deep violet, creating a dramatic contrast with the blue water. The water remains cold year‑round, so a quick dip is always refreshing but a wetsuit is advisable in winter.

Wildlife

The heather‑covered slopes support a range of birds, including meadow pipits, skylarks and occasional raptors. Early mornings bring a chorus of insects over the water’s surface, and the lake’s edge is dotted with bog cotton and other wet‑land plants.

Photography Tips

• Best light – early morning or late afternoon when the sun is low gives the lake its most vivid blue.
• Vantage points – the western rim looking eastward, and the col between Slieve Binnian and Slieve Lamagan, both provide dramatic reflections.
• Weather play – overcast days turn the water a deep slate, ideal for moody shots; after rain the greenish tint adds contrast.

What to See & Do

• Cool dip – After climbing Slieve Binnian or traversing the open heathland, a swim in the lake’s fresh, cool water is a rejuvenating reward. The water stays chilly even on warm summer days, so a quick splash is often enough to refresh tired limbs.
• Picnic by the water – A flat, grassy strip beside the lough provides an ideal spot for a packed lunch. The surrounding scenery offers a peaceful backdrop for families and couples alike.
• Scenic viewpoints – A short 600 m walk eastward leads to a col between Slieve Binnian and Slieve Lamagan, where you can enjoy a bird’s‑eye view of Ben Crom Dam and the surrounding peaks.
• Wildlife spotting – The heather‑rich slopes attract a variety of birds, including meadow pipits and skylarks. Early mornings often reveal the gentle hum of insects over the water’s surface.

Practical Information

Getting There

The walk starts at Carrick Little car park, located at the junction of the Head Road and Oldtown Road near Annalong Village. From the car park, follow the marked track northward alongside Annalong Wood, cross the small river, and continue up the gentle gradient past the Percy Bysshe outcrop. The lough comes into view shortly after the crossing.

Parking & Fees

There are two small gravel car parks at the trailhead. Both charge £3 for a day‑time stay and £5 for overnight parking (as reported by recent visitor guides). Spaces are limited, so arriving before 9 am on busy weekends is advisable.

Public Transport

The nearest bus stop is in Annalong (Translink services). From there it is a short walk to the car park, though most visitors prefer to drive. An alternative route is via Newcastle – a regular bus runs to Newcastle, from which a local taxi or rideshare can reach the car park.

Facilities

Toilets and refreshments are available in Annalong Village, a short drive (≈ 5 km) from the car park. No permanent facilities exist at the lough itself, so plan accordingly.

Access & Permissions

The walk traverses a mixture of public rights of way and traditional farm tracks. While the route is widely used, much of the land below 180 m elevation remains privately owned. Walkers are asked to respect landowners’ rights and follow the Leave No Trace principles.

Safety & Accessibility

• Sturdy, ankle‑supporting boots are essential; some sections are rocky and boggy.
• Waterproof clothing is recommended – mountain weather can change rapidly.
• The water is cold year‑round; a wetsuit or quick‑dip only is advisable.
• The route is not suitable for very young children or those with limited mobility.
• Start early and check the forecast to avoid being caught on the trail after dark.

Nearby Attractions

• Ben Crom Dam – visible from the col between Slieve Binnian and Slieve Lamagan; a short detour offers excellent photo opportunities.
• Annalong Harbour – a short drive to the coast, ideal for a post‑walk seafood meal. (Annalong Harbour)
• Slieve Binnian summit – for those wanting a full mountain experience, the summit provides sweeping views of the Mournes.

Blue Lough offers a blend of gentle mountain walking, striking scenery, and the simple pleasure of a cold dip in a pristine lake. Whether you are a family looking for a manageable day out or a seasoned hill‑walker seeking a rewarding break, the lough provides a memorable slice of the Mournes that is both accessible and free to enjoy.