Overview
The dry-fly method known as fishing the spent gnat was worked out on Lough Arrow in the early 1900s, and the lake is still rated one of Ireland’s best wild brown-trout fisheries. It’s a mesotrophic, spring-fed lake (Irish: Loch Arbhach) straddling the border of south County Sligo and County Roscommon, about 24 km south-east of Sligo town and 6 km north-west of Boyle. Fed by springs and limestone streams and draining north into the Unshin River, it runs roughly 6 km long by 2 km wide, clear enough to keep both anglers and wildlife happy.
Four islands break the surface – Annaghgowla, Inishmore, Inishbeg and Muck. The lake averages 9 m deep and drops to 33 m in places. It’s a Special Area of Conservation, framed by the craggy Bricklieve Mountains to the west and the Curlew hills to the south.
Angling & Water Sports
The trout season runs from 1 April to 30 September. Wild fish average around a pound, and the lake throws up trout to 6 lb. Check the current Inland Fisheries Ireland rules on permits, bag limits and size before you fish – they change, and it’s not worth guessing.
The lake’s limestone base and spring-fed inflows create a predictable insect hatch calendar that dictates fly-fishing tactics:
- Mid-April: Duckfly hatches dominate the evenings, best taken with wet-fly patterns like the Claret Bumble or Fiery Brown.
- Early May: The highly anticipated Mayfly (Ephemera danica) emerges across the lake, prompting dry-fly fishing with patterns such as the Yellow Wulff. May is the peak month for visitors.
- Late July & August: The Green Peter hatch appears, best fished on the surface with bright green patterns.
Boat hire is available a short walk from the Lough Arrow Touring Park, giving access to the deeper water and the island margins where the trout feed. Beyond angling, the calm water suits kayaking, paddleboarding and gentle rowing.
Wildlife & Nature
Winter is the season for waterfowl here. The reed beds and shallow margins hold mallard, teal, wigeon, goldeneye, tufted duck, pochard and red-breasted merganser, while great crested and little grebes, cormorants and mute swans work the open shoreline.
The surrounding woodlands and open plains provide habitat for songbirds and occasional raptors such as the hen harrier. The lake’s status as a Special Area of Conservation ensures its hard-water lake habitat remains protected, making it a reliable stop for migratory species and a quiet retreat for nature observers.
History & Heritage
The landscape around Lough Arrow is dense with prehistoric monuments and medieval ruins. Just 15 minutes from the lake, the Carrowkeel Megalithic Cemetery sits atop the Bricklieve Mountains. Dating to c. 3000 BC, this extensive passage-tomb complex features chambers marked alphabetically, some aligned to capture the light of the sun and moon during solstices.
On the eastern side of the lake lies the Moytirra East Court Tomb, a collection of standing stones tied to the Second Battle of Moytura – one of the great set-pieces of Irish mythology, and one whose themes have been claimed as an influence on everything from The Lord of the Rings to Star Wars. Nearby, the Heapstown Cairn rises 10 m high, another Neolithic monument thought to belong to the wider Carrowkeel complex.
North of the lake, the Labby Rock portal tomb stands as Ireland’s second-largest dolmen, featuring a massive 70-ton capstone. Local folklore ties Labby Rock to the legendary lovers Diarmuid and Gráinne, who supposedly slept there while fleeing Fionn mac Cumhaill. Celtic mythology also claims it as the burial place of Nuada of the Silver Arm, King of the Tuatha Dé Danann.
Medieval history is represented by Ballindoon Priory, a Dominican abbey founded in 1507 on the north-east shore. Founded by Thomas O’Farrell, the friary’s stone ruins overlook the water and echo the region’s turbulent religious past. On a rise above the lake stands Ballinafad Castle, a small Jacobean fort of the Plantation era; it’s freely accessible, with no entry fee. Adjacent to the modern touring park, a monument honours Ambrose O’Higgins, born in the nearby townland of Ballynary, and his son Bernardo, the liberator of Chile.
Accommodation & Facilities
The Lough Arrow Touring Park sits on the southern shore, offering an adult-only, 4-star camping experience. The site is fully equipped with 10-amp electric hookups, water points, a chemical disposal toilet, and a purpose-built amenity block with free showers and hot water.
Facilities include a laundry room, a campers’ shed with a freezer for fishing catches, and a club room featuring a book swap, DVD library, and log-burning stove. An on-site shop stocks basic groceries, ice cream, and breakfast essentials. Irish breakfast is served daily in the club room (booking required the night before). The park is cycle-friendly and welcomes dogs on a lead, with a dedicated exercise area available.
2026 Opening Dates: 12 March – 2 November.
Getting There & Nearby Attractions
Lough Arrow is easily accessed via the N4. From Sligo town, take the Castlebaldwin roundabout and follow brown camping signs for 8 km. From Boyle, take the Ballyfarnon turning (L1013) and follow signs for 8 km.
The towns of Boyle and Carrick on Shannon are within a 20-minute drive, offering supermarkets, pubs, and restaurants. For adventure activities, Lough Key Forest Park is just 15 minutes away, featuring zip-wires, nature trails, and boat hire. On clear days, the flat-topped silhouette of Benbulben is visible from the lake’s western shore.
Visitors planning to fish during the Mayfly hatch in early May should book accommodation well in advance, as this period draws anglers from across Europe and fills the local touring park quickly.