SHANNON, the principal river of Ireland. It flows with a bow-shaped course from N. to S. and S.W., from the N.W. part of the island to its mouth in the Atlantic on the S.W. coast, with a length of about 240 m. and a drainage area of 4544 sq. m. Rising in county Cavan in some small pools at the foot of Cuilcagh Mountain, the Shannon crosses county Leitrim, traversing the first of a series of large lakes, Lough Allen (9 m. in length). It then separates county Roscommon on the right (W.) bank from counties Leitrim, Longford, Westmeath and King's County on the left. In this part of its course it forms Loughs Boderg (7 m. long), Forbes (3 m.) and Ree (18 m.), and receives from W. the river Boyle and from E. the Inny, while in county Longford it is joined by the Royal Canal. It now separates county Gal way on the right from King's County and county Tipperary; receiving the Suck from W. and the Brosna from E., and forming Lough Derg (23 m.). Dividing county Clare from counties Tipperary and Limerick, the Shannon reaches the city of Limerick as a broad and noble river, and debouches upon an estuary 60 m. in length with a direction nearly E. and W. This divides county Clare on the right from counties Limerick and Kerry on the left.
A wide branch estuary, that of the Fergus, joins from N., and the rivers Mulkear, Maigne and Deel enter from S. From Lough Allen to Limerick, where the Shannon becomes tidal, its fall is 144 ft. With the assistance of short canals the river is navigable for light vessels to Lough Allen, and for small steamers to Athlone ; while Limerick is accessible for large vessels. The salmonfishing is famous; trout are also taken in the loughs and tributary streams. Carrick-on-Shannon, Athlone, Killaloe, and Castleconnel are favourite stations for sportsmen. The scenery is generally pleasant, and on the loughs, with their deeply indented shores and numerous islands, often very beautiful. These islands are in several cases sites of early religious settlements, while of those on the river-banks the most noteworthy is that of the seven churches of Clonmacnoise.
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)