Ireland has thousands of loughs, and most of them are a grey field of water you would not cross a county for. These six are not. They range from a black mountain tarn an hour from Dublin to a Kerry valley where the Milky Way reflects off the surface, and they ask different things of you – some you can see from the car, others want four hours on a ridge and a head torch. We have ranked them, with the parking, the best walk and the catch for each. If you only do one, the order tells you where to start.
1. Lough Tay (the Guinness Lake), Co. Wicklow
Lough Tay earned its nickname honestly: the water is almost black, and the Guinness family imported white sand to line a beach along the northern shore, so from the right angle the lake looks like a poured pint with the head settling. The east-facing granite cliffs of Luggala drop straight to the water behind it. Ernest Guinness bought the Luggala estate in 1937 as a wedding present for his daughter, and the lake has belonged to the family ever since – which is why you view it from the public road and not the shore. The screen credits are real: it stood in for the Viking village of Kattegat in Vikings, and John Boorman shot Zardoz and Excalibur here before Braveheart and P.S. I Love You turned up.
There are four viewpoints along the R759 (Sally Gap Drive), all free, all first-come. For a quick photo with no risk, use Viewpoint D, the Lough Tay Viewing Point – it gives a clear line to the lake without putting you near the sheer drops that catch people out at the others. If you want to walk, the J.B. Malone car park is the trailhead: an easy 8km out-and-back to Lough Dan, or the Djouce loop (6.5km, two to three hours) that climbs to a view straight down onto the black water. The honest catch is parking and the road. The viewpoints fill by mid-morning, several have drops that appear without warning, and the Military Road is narrow with heavy tourist traffic. It is roughly 55 minutes from Dublin city centre; arrive before 10am at weekends and you will get a space.
2. Coomasaharn Lake, Co. Kerry
For wildness, nothing else here comes close to Coomasaharn Lake, a dark, peat-stained basin about 4km west of Glenbeigh, walled in on three sides by ridges – Coomreagh at 593m, Teermoyle at 760m, Coomacarrea at 772m and Meenteog at 715m. The valley has been walked for a very long time: surveys have found Bronze-Age pathways more than 4,500 years old, rock-art panels and an ancient stone wall tracing the ridge, and the land sits inside the Reeks District, a gold-tier Dark Sky Reserve. The basin held the hunting grounds of the Fianna in legend, and nearby Seefin takes its name from Suí Fhinn, the Seat of Finn.
The reason most people make the drive is the Coomasaharn Horseshoe, a ridge circuit usually taken anti-clockwise from the lake’s outlet. The Short Loop is 12km over four peaks in four to five hours; the Long Loop adds Macklaun Mountain and runs to 24km and a full day. From the tops you get Dingle Bay and the strands at Rossbeigh and Inch to the north, the Skellig Coast and Valentia to the west, the Reeks to the east. The arête between Teermoyle and Coomreagh is the steep, exposed bit, and it turns slick in the wet. This is not a casual outing. Parking is a single small roadside lay-by at the end of a narrow unmetalled road that local farmers use, there are no facilities, and cloud can drop ridge visibility to near zero in minutes. Carry a map and compass alongside the GPS, pack a head torch even for a day walk, and check the forecast before you commit to the medium or long loops. After dusk the lake doubles the night sky, so a clear, moonless night is the one to aim for.
3. Glanmore Lake, Co. Kerry
Glanmore Lake sits deep in a valley on the Beara Peninsula, about 12km southwest of Kenmare, roughly 2km long and framed by the Caha Mountains and old dry-stone walls. At its centre is a small tree-covered island with stone remains of an early medieval hermitage, often called a crannog. When water levels drop, a low wooden bridge appears and you can cross to it on foot; otherwise it is a short paddle. The lake holds Atlantic salmon and sea trout and you can fish from the shore, and on a still day the water turns to a flat mirror of the surrounding peaks.
The best view is not from the shore at all. It is from the Healy Pass (R574), which climbs to 334m, where the lake unfolds as a ribbon set against Lackabane Mountain – the most photographed stretch on Beara, and at its best at sunrise or on a gold autumn afternoon. Down at water level, a quiet side road off the R574 reaches a forest-fringed track that loops part of the lake on gentle gradients and links to the Beara Way, and the Pedals & Boots Café nearby keeps trail maps. Access is free and year-round, but the site is unstaffed – no toilets, no shop, nothing on tap, so bring your own water and food. The mobile signal in the valley is patchy. Download your maps in Kenmare before you drive in, and if you want the Healy Pass shot, go for first light.
4. Lough Muckno, Co. Monaghan
Lough Muckno is County Monaghan’s largest lake, and the 900-acre leisure park wrapped around its eastern shore is the most family-ready stop on this list. Two wooded islands, Black Island and White Island, sit mid-lake, reached by a solid wooden bridge and laid out with orienteering courses, nature walks and peace gardens. The grounds were the Blayney family estate, which is where Castleblayney gets its name; in 1853 the twelfth Lord Blayney sold up to Henry Thomas Hope, who later owned the Hope Diamond, and the nearby Hope Castle still carries the name.
The trails run from a gentle 600m loop to the steeper High Road route, all through shaded oak and ash, and the lake is an international-standard coarse fishing venue with pike, bream, roach and tench under a 2017 catch-and-release bye-law. There is an active water-ski and wakeboard club that hosts national competitions you can watch from the shore. This is the one for a day with children or in poor weather: entry is free, the car park off the N2 is large, there are accessible toilets, a fenced super play area and a seasonal coffee kiosk, and Castleblayney has regular Dublin and Belfast buses a short walk away. Anglers need to plan ahead, though – island access runs through the Hope Castle gate, so arrange permits and access codes with Lakeside Angling in town a few days before you go.
5. Lough Ramor, Co. Cavan
Lough Ramor lies just south of Virginia, straight off the N3, in a shallow basin that gives the water a turquoise tint and keeps the shoreline calm – the opposite of the deep, dark lakes further west. It covers about 740 hectares, is a designated Natural Heritage Area, and is scattered with small islands. The notable one is Woodward’s Island, probably a fifth-century crannóg-church before it became a monastic site; by the 13th century the Augustinian abbey at Kells held it, and its overgrown ruins are still visible from the shore.
The lake is a working bird habitat. Great cormorants perch on the low islands, and whooper swans, grey herons, teal, wigeon and lapwings use the shallows, with chiffchaffs and willow warblers in the alder and willow scrub along the edge. For walkers there is a gentle 1.8km loop near Virginia past a children’s play area, picnic tables and a boardwalk that runs into the water, linking on into Deerpark Forest. The Caravan and Camping Park hires rowboats, canoes and small motorboats to reach the islands, and there is a designated swimming zone for summer. The free car park is small and fills on warm weekends, and the open basin is exposed to wind. Come early, pack a windproof layer even on a bright day, and bring binoculars – the birdlife is the reason to linger, especially in nesting season.
6. Lough Dan, Co. Wicklow
A short way south of its showier neighbour, Lough Dan is the quiet one: a boomerang-shaped ribbon lake at the foot of Luggala and Knocknacloghoge, 200m above sea level, with dark still water, conifer plantation and blanket bog all round. Most of the shoreline is private estate, but the north-western corner falls inside Wicklow Mountains National Park, with public access to a pebble shore at Coon Beach that feels a long way from the crowds at Glendalough. It has a quiet scouting heritage too – the Scouting Ireland national campsite is beside the lake, and hosted the Lough Dan ‘97 jamboree, which heavy rain and flooding cut short.
Three routes lead down. The most popular is the Old Military Road, a roughly 5km one-way walk along a historic gravel track, about three hours there and back; the Lough Dan House approach off Shinnagh Lane is a shorter 2km downhill but marshy in places; and the Ballinastoe route crosses the Luggala estate, where dogs are banned outright, lead or not. Here is the catch that puts it last: the lake was closed in the early 2020s after a run of anti-social behaviour and littering, and only reopened under controlled access in 2024. It stays open on the condition that visitors behave, so stick to the marked paths and carry every scrap of litter out. There is no public transport to any of the trailheads, the track is slick when wet, and fishing and camping are both off the table. Come by car, bring waterproofs and proper boots, and if Ballinastoe is full by the time you arrive, that is your sign to have driven earlier.
Before you go
These lakes have no lifeguards and the water stays cold all year, so swim only where you are sure of yourself and keep children well back from unfenced shores and sheer drops. The good car parks are small, free and full by mid-morning at weekends, so treat an early start as part of the plan rather than a bonus. Pack a waterproof and a map or offline GPX even on a bright morning – mountain weather turns fast and the valley signal drops out – and take all your litter home, because at least two of these spots stay open only because people do.
