Lough Ennell () is a lake near the town of Mullingar, County Westmeath, Ireland. It is situated beside the N52 road, off the Mullingar/Kilbeggan road. The lake is part of the Lough Ennell Special Protection Area. It is long by wide, with an area of about . Lough Ennell has a large area of shallow water with nearly two-thirds of its area being less than 25 feet (8 m) and almost half of it being under deep. The lake produced Ireland's largest ever lake brown trout at 26 lbs (11.8 kg). Lough Ennell is dotted with islands, many of which have now become attached to the shoreline as the levels of the lake have changed.