|Its name means the Lake of the Marsh. It has a surface of 116 ha. An outlet from the lake runs into the River Feorish. Fish in the lake include Pike, Perch, Roach, Bream and Tench.
There are many crannogs in Lough Meelagh. Crannogs are man-made islands of timber and rock and were used for defence and habitation. They were occupied during the early Christian period through to the 17th century.
The Department of the Environment, Community and Local Government in cooperation with the Tree Council of Ireland, Roscommon County Council and the Department of Arts, Heritage and the Gaeltachth devised a tree planting scheme for 2016 to commemorate the centenary of the 1916 Easter Rising. This scheme was for towns and villages which won the overall award in the Tidy Towns Competition since 1958.
As winners of the Tidy Towns Competitions in 1993 and 2003, Keadue was gifted seven oak trees to represent the seven signatories to the Proclamation and these trees were planted as part of National Tree Week 2016 at Lough Meelagh Amenity Site.