Overview
The Shannon Pot, the traditional source of Ireland’s longest river, sits in Derrylahan – a quiet townland in the civil parish of Templeport, County Cavan. The pot is a dark, roughly circular pool about 16 metres across, fed from below by an underground aquifer, and from it the Shannon sets off across the middle of the country to the Atlantic. The name Derrylahan comes from the Irish Doire Leathan, ‘the wide oak-wood’, after a forest long since gone; what remains is a patchwork of small loughs, rivers and forestry, with the R206 running through the middle of it.
Be clear about what you’re coming for. This is a short walk to a modest pool, worth the stop for the idea of standing where a great river begins, not for a grand spectacle. Give it twenty minutes and pair it with a stretch of the Cavan Way.
The Shannon Pot
Geologically the pot is a karst resurgence: water that fell as rain across the surrounding hills sinks underground and wells back up here, which is why the level rises and falls with the weather rather than holding steady. Divers have followed the flooded passage down to about 14.6 metres. From the car park a short marked trail reaches the rim in a few minutes, and interpretive boards at both the car park and the pool fill in the detail.
The legend is older than the geology. Sionnan, granddaughter of the sea-god Lir, is said to have come here looking for the Salmon of Wisdom; the salmon, angered, made the pool overflow and drowned her, and the river that rose bears her name still.
History and archaeology
The pot has drawn notice for centuries. The earliest written mention is in the 14th-century Book of Magauran, where the poet Giolla na Naomh Ó hUiginn praises the well from which the Shannon comes. John O’Donovan’s 1836 Ordnance Survey field notes describe it as a ‘round deep pool throwing out a stream of considerable size’ and record the local names Poll Lagan Sionna and Lag Bhun na Sionna.
The townland holds quieter traces too: a steep-sided circular earthen mound about 4.2 metres across, masonry crossings including the Shannon Bridge, and scattered lime-kilns and stepping stones along the Black River, all marking older patterns of farming and crossing the water.
Lakes, woodland and wildlife
Away from the pot, water dominates the scenery. Three small loughs – Carricknahurroo, Derrylahan and Lattone – sit among the fields, and the Black River and several mountain streams thread the townland. The surviving oak-wood holds a damp, shaded microclimate good for mosses and lichens; birdwatchers pick out hawfinch, treecreeper and buzzards, while the loughs carry brown trout and pike.
Walking the Cavan Way
The Shannon Pot sits on the Cavan Way, the 26-kilometre waymarked route between Blacklion and Dowra, so the pot makes a natural stop on a longer walk rather than a destination in itself. Derrylahan has no formal trails of its own beyond the short path to the pot, but its rural lanes and the R206 are quiet enough for easy walking and cycling.
For more on the doorstep, the Cuilcagh Lakelands Geopark and Cavan Burren Park open up longer routes through limestone pavement and glacial woodland.
Practical information
The Discovery Centre (not yet open)
A €10 million Shannon Pot Discovery Centre is being built at the site, funded by Fáilte Ireland (€7.4 million) and Cavan County Council, with a treetop walk planned alongside it. The sod was turned in 2024, but weather delays have pushed the opening back, and as of mid-2026 it has not opened. A 500-metre interpretive trail is part of the same project. Until it’s finished, treat the pot as an outdoor stop only.
Access and transport
Derrylahan is reached on the R206, which links the townland to Bawnboy and Glangevlin. A car is by far the most practical option; the nearest bus stops are in Bawnboy, roughly 8 km away.
Facilities
The car park is free, with ample parking and a picnic area. There are no toilets or café at the pot itself yet – those come with the Discovery Centre. The path to the rim is unpaved and can be uneven for wheelchairs or pushchairs.
Nearby
- Cavan Burren Park – walking trails through ancient woodland and glacial stone pavements.
- Sean MacDiarmada’s cottage – the thatched birthplace of the 1916 leader, in Kiltyclogher just over the Leitrim border, about 20 minutes’ drive.
- Cuilcagh Mountain – hill-walking with views across the lakelands.
- Annagh Lake – swimming, angling and a historic crannóg, a short drive away.
- Cavan County Museum – regional archaeology and folklore, including the Killycluggin Stone.
- Dowra – a riverside village at the far end of the Cavan Way.
Go early or late in the day for the best light on the pot and the fewest people, and after a few days of rain if you want to see the water genuinely moving.