Shannon River Basin a measurement of . When added to the Shannon's estuary this gives a total river flow of , which makes it the longest river within the River Shannon basin (from source to mouth)— longer than the Shannon Pot source. Thus the Boyle-Shannon river can be regarded as having the longest natural river flow in Ireland. The River Shannon Basin touches more than half (17) of Ireland's counties:- Limerick, Clare, Tipperary, Offaly, Westmeath, Longford, Roscommon, Kerry, Galway, Leitrim, Cavan, Sligo, Mayo, Cork, Laois, Meath and Fermanagh. There are many towns situated in the Shannon Basin. Towns and Villages (with 2011 populations)
County Offaly the county before joining Brosna near the town of Ferbane. The Grand Canal also runs across the county from Edenderry on the north-east to Shannon Harbour before joining the Shannon. The county contains many small lakes from Lake Boora to Pallas Lake and it also contains 42 hectares of swamp land. There are a number Eskers in the counties landscape including Esker Riada. Offaly largely comprises a flat landscape and is known for its extensive bog and peatlands. There are many large bogs in Offaly including the Bog of Allen, Clara bog, Boora bog and Raheenmore Bog which are spread