Roman Catholic Diocese of Ardagh and Clonmacnoise from the currently-used names) Roman Catholic Diocese of Ardagh and Clonmacnoise The Diocese of Ardagh and Clonmacnoise () is a Roman Catholic diocese in Ireland. The diocese is entirely within the Republic of Ireland and contains most of counties Longford and Leitrim, with parts of counties Cavan, Offaly, Roscommon, Sligo and Westmeath. The main towns in the diocese are Athlone, Ballymahon, Carrick-on-Shannon, Edgeworthstown, Granard and Longford. The union of the sees of Ardagh and Clonmacnoise, which had been proposed in 1709, was carried into effect following the death of Stephen MacEgan, Bishop of Meath on 30 May 1756, who had
County Offaly Mountain which are the county's second and third highest peaks. Croghan Hill rises from the Bog of Allen and is located in northern Offaly. Although only 234 metres high, it is known for its view over the surrounding area and it stands out by itself. The floodplain of the River Shannon is in the north-western part of the county. The River Camcor runs through the town of Birr and is a Wild Trout Conservation Area. The River Brosna runs across the county from Lough Owel in Westmeath to Shannon Harbour. Silver River runs through several towns in the south of