County Leitrim shares border with County Donegal
Geography
Leitrim is the 26th of the 32 counties by area  (21st in size of the 26 counties of the Republic) and the smallest by population. It is the smallest of Connacht's five counties in both size and population. Leitrim is bordered by the counties of Donegal to the north, Fermanagh to the north-east, Cavan to the east, Longford to the south, Roscommon to the south-west and Sligo to the west. Fermanagh is in Northern Ireland while all the other neighbouring counties are within the Republic of Ireland.
Leitrim has a hilly and mountainous landscape in its northwest and is relatively flat in the southeast, each separated from the other by Lough Allen in the middle of the county. Leitrim has the shortest length of coastline of any Irish county that touches the sea. At Tullaghan, the coastline is only 4.7 kilometres (2.9 mi) long.  The Shannon is linked to the Erne via the Shannon–Erne Waterway. Notable lakes include:
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