It is located in north County Donegal close to the eastern boundary of Glenveagh National Park.

[2] Gartan Lough is fed by the Bullaba River entering at its southern end.

The lake drains northeastwards into the River Leannan, which in turn enters Lough Fern.

[2][4] Fish species in Gartan Lough include Arctic char.

Gartan Lough is part of the Leannan River Special Area of Conservation.