The
Shannon River Basin consists of the area containing
Ireland's longest river, the
River Shannon, and all of its tributaries and lakes. The official
Ordnance Survey Ireland length of the Shannon from its
Shannon Pot source is 224 miles (360.5 km) made up of 63.5 miles (102.2 km) tidal water flow and 160.5 miles (258.3 km) freshwater flow.