Lough Gill () is a freshwater lough (lake) mainly situated in County Sligo, but partly in County Leitrim, in Ireland. Lough Gill provides the setting for William Butler Yeats' poem "The Lake Isle of Innisfree". Location and environment Lough Gill is about 8 km or 5 miles long and 2 km or 1 mile wide. The Lough Gill system consists of the river Bonet that flows into the eastern end of the lake and the River Garavogue which drains the lake to the west near Sligo Town. The picturesque lake is surrounded by woodlands, such as Slish Wood, Dooney Rock, and Hazelwood all of which contain popular nature trails and viewing points along the lake. The wooded hills of Slieve Killery and Slieve Daean dominate the south shore. It is a popular location for birdwatchers. Flora and fauna Lough Gill has a unique microclimate and is noted for its high number of rare or scarce animal and plant species. It is part of the Lough Gill SAC (Special Area of Conservation) for habitats listed on Annex I and II of the E.U. Habitats Directive, including two with priority status: alluvial forest, orchid-rich calcareous grassland. The vegetation of the area was dominated by mixed woodland from 4,600 BC to at least 1400 AD. Scots pine was dominant until 3,400 BC. In a scientific study, Arbutus unedo pollen was found at Slish Lake dating from as early as 100 AD, and so it is considered native to this area. The woods surrounding the lake are dominated by oak (Quercus spp.), rowan (Sorbus aucuparia) and willows (Salix spp.). The shores of the lake are home to the world's northernmost specimens of the rare Mediterranean strawberry tree (Arbutus unedo). It is a small evergreen tree of the family Ericaceae, which in Ireland can grow to be a forest tree, reaching heights of up to 15 metres. Its Irish name is caithne. The lake shore and surroundings support several rare plant species, including yellow bird's-nest (Monotropa hypopitys), lady's mantle (Alchemilla glaucescens), ivy broomrape (Orobanche hederae), black bryony (Tamus communis), intermediate wintergreen (Pyrola media) and bird's-nest orchid (Neottia nidus-avis). It is also home to the following rare or protected species: sea lamprey, river lamprey, brook lamprey, white-clawed crayfish, Atlantic salmon and otter. The Lough Gill water system gets a very early run of spring salmon. A small colony of common terns breed on the lake's islands