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Lough Oughter

A flooded drumlin landscape in Cavan that is less a lake than a maze of water between hundreds of small hills.

Updated 28 August 2026

Typelake system
WhereCavan
Nearest cityCavan town about 10 km; Killeshandra about 8 km
Best seasonApril to October
Time to allowHalf a day
Getting thereKillykeen Forest Park off the R199, or minor roads around the shore; car, or by boat
EntryFree

Lough Oughter is not really a lake with a shape. The last ice sheet left this part of Cavan covered in drumlins - low rounded hills of glacial debris - and when the water rose it filled every hollow between them, producing an intricate network of channels, bays and islands over a large area, with the boundary between land and water hard to define on any map. Boating through it is genuinely disorienting. On one of the islands stands Clough Oughter Castle, a circular thirteenth-century tower on a small artificial island, reachable only by water; it was where Owen Roe O'Neill died in 1649 and was one of the last strongholds to fall in that period. Killykeen Forest Park on the western side has trails, cabins and water access. The lake is a major coarse fishery. Navigation without local knowledge is confusing and the shore is largely reed and private land.

The landscape

  • The drumlin maze - water filling every hollow between rounded hills.
  • Clough Oughter Castle - a circular thirteenth-century tower on an island.
  • Killykeen Forest Park - the main access point, with trails and water frontage.
  • The fishery - one of the better coarse fishing systems in the country.

When to go

April to October for the water and the trails. Fishing runs year-round. Winter flooding raises levels and makes shore access poor.

What to expect

The castle can only be reached by boat and there is no landing service - most people see it from the water or across it. Navigation is confusing without local knowledge. Shore access is limited by reeds and private land.

Nearby

Cavan Burren Park is west; Killykeen and Killeshandra are on the lake.

Key facts

Area15 km² (5.7 sq mi)
Length12 km (7.5 mi)
Location54.0055° N, 7.4772° W · map

Source: Wikidata, item Q3756406, read on 18 October 2026.

What to pack for Lough Oughter

Chosen from what this place is for. Tap a kit for the full checklist.

  • Broken-in walking shoes or boots - Grip and ankle support matter more than looks; never hike in brand-new boots. Find on Amazon
  • Travel rod + reel - A packable multi-piece rod fits in a case and covers most holiday fishing. Find on Amazon
  • Warm base layers - Merino or synthetic against the skin - never cotton, which chills when damp. Find on Amazon
  • Layers + a waterproof shell - Mountain weather turns fast; a packable rain jacket saves the day. Find on Amazon

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Opening times, ticket prices and seasonal closures change - check the official source before you go: official site.

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