Shannon
a large river in the W. of Ireland, and one of the finest in the British Islands. It has a length of 220 miles, and is divided into the Upper and Lower Shannon. The Upper Shannon, by far the longest and narrowest part of the river, rises in the mountains of UIthe mountains of Ulster, at the N. W. extremity of the county of Cavan from the Cuilcagh Mountains, and flowing S. enters and passes through Lough Allen, till, quitting the county of Leitrim, it flows S. and E. and S. W. to the town of Banagher, forming from this portion of its course the boundary between Connaught and Leinster. From SHANNY Banagher the river has first a S. W. and then a S. course, till, a little above the city of Limerick, it divides into two branches, which, flowing round King's Island, the most ancient part of the city, unite below to form the Lower Shannon.
From its rise in Cavan to its encircling the King's Island, the river has a length of 180 miles. In this course the river is greatly interrupted by shallows, falls, and rocks. The Lower Shannon, from Limerick to the mouth of its estuary the Atlantic, has a length of 40 miles and a breadth of from 1 to 7 miles; though the channel in places is obstructed by islands, rocks, and shoals. It has, however, good anchorage everywhere, and forms a harbor of refuge for ships against the force of W. gales. ry in