River Erriff

Overview

The River Erriff (Irish: An tOirthir) is a short, energetic waterway that carves a 16-kilometre glacial valley across the western edge of County Mayo before emptying into Killary Harbour. Fed by the Owenree and Owenmore streams near Glennacally, the river runs parallel to the N59, passing under the historic Aasleagh Bridge and plunging over a series of cascades just before the Galway border. Classified as a spate river, the Erriff responds quickly to rainfall, shifting from gentle riffles to a roaring cascade within hours. This rapid change in flow shapes the river’s character, creating deep holding pools for fish and a dynamic landscape for walkers and paddlers.

History & Conservation

The Erriff Valley stretches from the historic village of Aughagower in the east to the Connemara mountains and Killary Harbour near Leenane. The valley’s backdrop is dominated by the “Devil’s Mother” peak, a distinctive mountain silhouette that has guided travellers and shepherds for centuries. Historically, the river was managed as a private salmon and sea-trout fishery, with Aasleagh Lodge serving as the headquarters for the Marquis of Sligo.

In the early 1990s, nearby salmon farming operations caused significant water quality issues, threatening the river’s wild fish populations. A coordinated conservation effort involving local stakeholders, environmental agencies, and the fishery management team implemented stricter monitoring and habitat restoration. The strategy worked: salmon runs have steadily rebounded, with 200 to 300 returning fish recorded annually in recent years. The recovery stands as a practical example of how targeted management can restore a pressured wild waterway.

Aasleagh Falls

Located just a kilometre north of the Galway-Mayo border, Aasleagh Falls drops dramatically over limestone ledges into a rocky plunge pool. The falls are most impressive during high water, when the river’s volume transforms the cascades into a wide, thundering curtain. The site gained recognition after featuring in Jim Sheridan’s 1990 film The Field, where the dramatic backdrop framed one of the movie’s most memorable sequences.

There is no formal footpath to the viewing area, so visitors should expect a short walk over uneven, occasionally muddy ground. Two small car parks on either side of the R335 provide free access, but space is limited and often shared with anglers and walkers. The falls are free to visit year-round, and the surrounding valley offers quiet spots for photography and picnics.

Fishing the Erriff

The river is divided into nine beats, each allocated to anglers on a rotating daily basis. Fly-fishing is the standard method, though the fishery manager may permit spinning, worm, or prawn under specific conditions. Most beats allow two rods, with a few accommodating up to three. The fishing season runs from 1 April to 30 September for salmon, 1 June to 30 September for sea trout, and 15 February to 30 September for brown trout.

Beat 9, which includes the Falls Pool, typically commands a slightly higher rate due to its popularity. Anglers can also fish the two adjoining loughs, Tawnyard and Derrintin, which support salmon, sea trout, and brown trout. Only fly-fishing and dapping are allowed on the loughs, and boats with outboard motors can be arranged through the lodge. Permits are issued by the Fishery Manager at Aasleagh Lodge (095 42382). Advance booking is recommended for peak summer weeks, and a gillie can be hired for an additional fee.

Walking & Kayaking

The Western Way long-distance trail uses the Erriff valley for its opening five kilometres, starting at Aasleagh and heading east. The route passes Houston Bridge, enters the Coillte-managed Tawnyard Forestry, and offers a short detour to Tawnyard Lough, where a crannog island dates back over 5,000 years. From there, the trail climbs Sheeffry Pass, revealing sweeping views of Saint Dabeoc’s Heath and, on clear days, the distant profile of Croagh Patrick.

For paddlers, the lower kilometre of the river presents a grade 2–4 run that culminates in the 12-foot drop at Aasleagh Falls. Access is generally permitted outside the official fishing season (October to March). The left-hand channel is preferred for most runs, while the right channel only becomes navigable in flood conditions. Paddlers should note a small cauldron with a strong tow-back near the falls and a concrete bridge that requires careful navigation.

Practical Information

Getting there: The nearest town is Leenane, approximately 5 km east of the falls. Bus Éireann route 450 connects Westport and Leenane, and taxis or shuttles can bridge the final stretch. The N59 road from Westport to Leenane runs alongside the river for much of its length, with numerous pull-offs for photography.

Access & Parking: Aasleagh Falls is reached via a short detour north of Leenane on the R335. Two small, free car parks sit near a sharp bend. The ground to the falls is unpaved and can be slippery after rain. Aasleagh Lodge remains wheelchair-accessible, though the natural terrain around the river and trailhead is uneven.

Nearby Attractions:

• Ballina – Known as Ireland’s Salmon Capital, offering additional fishing on the River Moy.
• Ballycroy National Park – Wild Nephin landscape with extensive bog and mountain trails.
• Ben Gorm – A prominent mountain ridge popular with hikers seeking panoramic valley views.
• Killary Harbour – Ireland’s only fjord, ideal for boat trips and coastal walks.

Permits for the Erriff must be arranged through the lodge office, and water levels should always be checked before planning a fishing or kayaking trip. The river’s rapid response to rainfall means conditions can change quickly, so checking the forecast and speaking with the fishery manager on the day will ensure a safer, more productive visit.