Dividing Ireland almost in two and dominating the midlands landscape, the River Shannon has acted as a formidable barrier to movement from East to West while providing a marine highway from North to South. It is the longest river in both Ireland and Britain, and has influenced the military, social and economic history of  Ireland since the beginning of  time. Travelling over 200 miles from its source to the sea, it is home to over a dozen lakes and more then a hundred islands. It is joined on its journey by dozens of smaller rivers and streams some of which are also navigable.

The River Shannon is now the backbone of a vast network of inland waterways, joined to the Erne via the newly restored Shannon-Erne link, formerly known as the Ballinamore and Ballyconnell Canal. The Grand Canal connects Dublin and the East coast, while the Barrow Navigation makes it possible to travel to the South East. entering the sea at New Ross, Sailing
southwards down river brings the traveller through Limerick and out to the Atlantic Ocean with the possibility of sailing to New York if the fancy takes you. Future developments include the possibility of reopening the Ulster Canal, which connects The Erne to Lough Neagh, Ireland's largest lake.

Navigation is simple with the deep channel being marked to keep sailors on course. The Erne has only one lock, the Shannon six, and the Shannon - Erne link sixteen

In 300BC the Roman cartographer Ptolemy mapped the river when it was an important trade route from Europe and during the first millennium AD Viking long boats sailed up through mists of the midland bogs to loot the medieval monastery at Clonmacnois and a found a town at Rindoon on Lough Ree. The formidable High King of Ireland Brian Boru, who broke the power of the Vikings at the battle of Clontarf in 1014, deployed a fleet of war galleys on Lough Ree to deal with the Viking threat.

Cromwell's famous edict