It is located in the Connemara area of County Galway.

The Twelve Bens mountain range lies to the north of the lake, with Benlettery directly overlooking.

Ballynahinch Lake is fed by Derryclare Lough at its eastern end (which is in turn fed by the neighboring Lough Inagh), and it drains to the south via the small Owenmore River – also called the Ballynahinch River, and not to be confused with the Owenmore River (County Mayo) – which in turn enters Bertraghboy Bay.

[2] Fish species in Ballynahinch Lake include salmon and brown trout.

[4] Ballynahinch Lake is part of The Twelve Bens/Garraun Complex Special Area of Conservation.