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 out across the county with the Bog of Allen extending into four other counties. The county consists of approximately 42,000 hectares of peatlands which is 21% of Offaly's total land area. Offaly contains approximately of forest and woodland area, which only amounts to 4.5% of the county's land area. This includes woodlands within the Slieve Blooms and the Lough Boora Parklands. Roughly 75% of Offaly's forested area is Conifer High Forest. The following are the historical baronies located in County Offaly: One of the earliest known settlements in County Offaly is at Boora bog which dates back to the Mesolithic