county in the province of Ulster, northeastern Ireland. It is bounded by Counties Monaghan (northeast), Meath, Westmeath, and Longford (south), and Leitrim (northwest). Northern Ireland lies to the north. Northwestern Cavan comprises uplands, intersected by valleys, declining toward the main valley of the River Erne, where the main features are the drumlins (long, oval mounds) that alternate with lakes, rivers, peat bogs, and pastures. East of the Erne Valley is a line of slate and shale hills
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