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 6.5 km (4.0 mi) long by 2 km (1.2 mi) wide, with an area of about 12 km2 (4.6 sq mi). Lough Ennell has a large area of shallow water with nearly two-thirds of its area being less than 25 feet and almost half of it being under 10 ft (3.0 m) deep. The lake produced Ireland's largest ever lake brown trout at 26 lbs (11.8 kg).

Mullingar is the county town of County Westmeath in Ireland. It is the third most populous town in the Midland Region, with a population of 22,667 in the 2022 census.