county in the province of Connaught (Connacht), Ireland. It is bounded by Northern Ireland (east) and Counties Donegal (north), Cavan (east), Longford (south), and Roscommon and Sligo (west). The southern part of the county is a lowland covered by glacial drifts; most of it is used as farmland, though there are peat bogs and many small lakes. The western boundary follows the River Shannon, on which boats can ascend to Carrick-on-Shannon, the county town (seat). At Drumshanbo, close to Lough (lake) Allen, the terrain changes to a series of plateaus, mainly 1,400 to 1,800 feet (425 to 550 metres) high. There are relics of past ironworks in the south and some coal seams, with many traces of past mining. The plateaus are split up by a number of deep valleys, in one of which Lough Allen covers about 14 square miles (36 square km).
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