At 5 by .5 kilometres (3.11 by 0.31 mi) it is the largest lake in East Clare after Lough Derg.

The lake is well known for its coarse fishery, with pike, perch, bream, rudd and eel.

The lake is the home or resting place for water-fowl and wading birds that include whooper swan, great crested grebe, grey heron and greater white-fronted goose.

[2] As of 1901 the Killanena DED included the townlands of Acres, Corbehagh, Derreendooagh, Derrycarran, Derryfadda, Derrynaveagh, Dooglaun, Doorus East, Doorus West, Gortaveha, Gortnamuinga, Islandmore, Killanena, Knockanena, Knockatunna, Knocknageeha, Knocknahannee, Lannaght, Pollaghanumera, Reanahumana, Scalp and Spaightspark.

Although it did not have electricity, gas or public water or sewage supply at the time, it had plentiful fine wells.