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Lough Derg Key Facts

Area:      13,000 hectares (32,000 acres) of non-tidal waters – all of which are navigable.

Width:    12 km (7.5 miles) wide at its widest point.

Length:   It stretches for 35km (22 miles) north to south.

Relative Size:  Largest of three lakes on River Shannon, the longest river in Ireland and Great Britain. It’s also the second largest lake in the whole of Ireland, Lough Neagh in Northern Ireland being the largest.

Geology:  Lough Derg is a lake of two parts. Its northern half displays headlands, islands and shoals of boulder-rich glacial drift. The southern end has dramatic features as its deep (almost 30m) waters are channelled through the gap it cut in the mountains.

Location:  Lough Derg is centrally situated on the River Shannon (see Lough Derg and Ireland Map) in the heart of Ireland.  The lake is just 25 kms (15 miles) from Limerick City and 48 kms (30 miles) from Shannon International Airport.   It’s surrounded by Counties Clare, Galway and North Tipperary, with South Offaly and Limerick also nearby on the banks of the River Shannon, as the river enters and leaves the lake respectively on its way to the Atlantic Ocean.

Rich History:  The lake shores have been settled since prehistoric times and its channel is part of one of Ireland’s oldest routes.  Brian Boru, the legendary 11th century High King of Ireland, had his great palace at Killaloe on the southern tip of the lake.    A doorway through which the legendary King passed over 1,000 years ago can be seen at St. Cronan’s Church, Tuamgraney,  Co. Clare.

You can also see Brian Boru’s Fort (Beal Boru in Irish) off the Killaloe – Scarriff Road on the Clare side of the lake. This is a spur of land which commands the point where the lake narrows into the River Shannon and it’s where cattle designated as tribute for the Dalcassian chiefs led by Brian were driven across the river in ancient times.