Gaelforce Great Lake Swim

Where the River Shannon broadens into the expanse of Lough Derg, open water swimmers gather along the banks of Portumna. The Gaelforce Great Lake Swim is an open water swimming race in the fresh water of Lough Derg, at Portumna in Connacht, Ireland. Organised by Gaelforce Events, the event forms one third of the Gaelforce Great swim trilogy. Swimmers enter the lake from the dedicated bathing area of Portumna, stepping out into a wide natural basin where river currents yield to still lake waters. Competitors choose between three distinct course lengths: a 750-metre dash, an intermediate 2,000-metre course, and a 3,900-metre endurance route. Taking place in July, the competition often catches Lough Derg at the height of its summer warmth.

During sunny editions, water temperatures have climbed to around 22°C (72 °F) beneath afternoon air temperatures reaching 30°C (86 °F). The course loops over open water framed by small green islands and the distant silhouettes of ancient stone ruins. Out on the course, swimmers settle into an rhythmic cycle of sighting marker buoys, keeping direction against soft swells, and reading the water below. Looking down through the lake reveals submerged weeds waving across the bottom and curious freshwater fish darting across. On the longest distances, some swimmers have reported a temporary pins-and-needles numbness in their fingers after about two kilometres, a sensation that clears within minutes of leaving the water and warming up.

Lough Derg: Ireland's great Shannon lake

Lough Derg is the second-largest lake in the Republic of Ireland and the third-largest across the entire island of Ireland. Its vast freshwater basin reaches a maximum depth of 36 metres, holding immense reserves of water as it stretches southwards. Just north of the lake entrance near Portumna, Hayes Island splits the incoming River Shannon into two distinct branches, measuring roughly 79 metres on the County Tipperary side and 73 metres on the County Galway side. Further downstream beyond the lake, the Shannon tumbles over the Doonass falls, which form the largest waterfall along the entire course of the river. During the nineteenth century, the lake developed into an essential transportation route, linking Limerick to Dublin through an extensive canal network.

Ireland's first inland RNLI lifeboat station was created at Dromineer. Today, the peaceful water and secluded islands support thriving wildlife; in 2012, a pair of white-tailed eagles successfully established a nesting site on one of the lake's quiet islands. Other tributaries feed into Lough Derg, enriching its diverse aquatic habitats. Farther up the Ballyfinboy River at Ballinderry, an electric fishing survey confirmed brown trout and salmon moving through the currents. Around twelve kilometres away along the banks of the Woodford River, naturalists can find the rare bird cherry shrub growing in the damp woodland margins. Roughly twelve kilometres from the swim site lies Redwood Bog, a 326-acre raised bog situated along the flood plain of the Little Brosna River.

Established as a national nature reserve in 1991 and designated as a Special Area of Conservation, the bog preserves an internationally recognized flood plain ecosystem and wildfowl refuge. It holds the last largely intact peat dome on the flood plain margin, complete with Sphagnum moss lawns, hummocks, flushes, quaking zones, and deep bog pools.

Dugout canoes and fortresses along the Shannon shore

Humans have lived alongside and traveled across these waterways for thousands of years. In the Neolithic era, the surrounding landscape consisted of dense mixed woodland interspersed with flooded wetlands, offering essential travel corridors and abundant timber. Around five kilometres from Portumna at Stoneyisland, researchers recovered a prehistoric dugout canoe buried five feet deep in peat, alongside the remains of a man who drowned in an ancient lake before the bog formed. Chemical analysis of his remains showed that freshwater lake fish formed an important part of his regular diet. West of the River Shannon, about four kilometres from the race area, stands Derryhiveny Castle. Right along the lake shore in Portumna itself, Portumna Castle is near where the Shannon enters Lough Derg, while nearby Portumna Abbey is along the northern shoreline.

About thirteen kilometres from the swimming area, where the River Shannon meets the Little Brosna River at the historic boundary of Munster, Leinster, and Connacht, engineer Thomas Rhodes built Victoria Lock during the 1840s. Measuring 142 feet by 40 feet, this working stone chamber continues to guide private boats and holiday cruisers through the river system, situated close to the disused historic Hamilton Lock. Near Victoria Lock on Moran Island stands a stone Martello tower built around 1811 to guard the rapids and shallow river crossings from potential French invasions. The tower formed part of a river defense network that reinforced Keelogue Battery on neighboring Incherky Island.

Portumna Forest Park and the harbours

Boating traffic is accommodated by two separate waterfronts: Connacht Harbour on the riverbank and the New Harbour facing directly out onto the broad expanse of Lough Derg. A historic five-span road bridge built in 1911 links the riverbanks, recognized as the largest early-twentieth-century swing bridge anywhere in Europe. Portumna Forest Park is a vast public reserve encompassing nearly 600 hectares on the northern shore of Lough Derg. Within its sheltered woodland paths rest the remains of a fifteenth-century Cistercian abbey. The park environment encompasses open spaces, marshes, open water, and offshore islands that shelter diverse plant and animal life. Walking tracks and elevated observation points run along the water's edge. On race weekend, the Portumna bathing area turns into a lively lakeside festival. Swimmers emerging from the cool lake water can recover with outdoor sauna sessions, lakeside yoga, and Tai Chi classes. Musicians provide a welcoming place to celebrate a memorable swim in Ireland's great midland lake.