Lough Sheelin is a limestone freshwater lough

Lough

A lough is a body of water and is either:* A lake* A sea lough, which may be a fjord, estuary, bay, or sea inlet.It can also be used as a surname, with various pronunciations: law, loch, low, lowe, loth, loff....

 (lake

Lake

A lake is a body of relatively still fresh or salt water of considerable size, localized in a basin, that is surrounded by land. Lakes are inland and not part of the ocean and therefore are distinct from lagoons, and are larger and deeper than ponds. Lakes can be contrasted with rivers or streams,...

) in Ireland

Republic of Ireland

Ireland , described as the Republic of Ireland , is a sovereign state in Europe occupying approximately five-sixths of the island of the same name. Its capital is Dublin. Ireland, which had a population of 4.58 million in 2011, is a constitutional republic governed as a parliamentary democracy,...

 located in County Westmeath

County Westmeath

-Economy:Westmeath has a strong agricultural economy. Initially, development occurred around the major market centres of Mullingar, Moate, and Kinnegad. Athlone developed due to its military significance, and its strategic location on the main Dublin–Galway route across the River Shannon. Mullingar...

, County Meath

County Meath

County Meath is a county in Ireland. It is part of the Mid-East Region and is also located in the province of Leinster. It is named after the ancient Kingdom of Mide . Meath County Council is the local authority for the county...

 and County Cavan

County Cavan

County Cavan is a county in Ireland. It is part of the Border Region and is also located in the province of Ulster. It is named after the town of Cavan. Cavan County Council is the local authority for the county...

 near the village of Finea and the town of Granard County Longford

County Longford

County Longford is a county in Ireland. It is part of the Midlands Region and is also located in the province of Leinster. It is named after the town of Longford.Longford County Council is the local authority for the county...

.

The lake is naturally populated by brown trout

Brown trout

The brown trout and the sea trout are fish of the same species....

s whose native stocks had depleted in recent years, hence the Central Fisheries Board stocking with farm reared the lake for the pleasure of anglers.
Trout stocks are estimated to be over 100,000.