Lough Beg is a small freshwater lake north of Lough Neagh in Northern Ireland. The lake is located on the border between County Londonderry and County Antrim. The Lower Bann flows into it from Lough Neagh at the southern end and continues on its route to the sea from the northern end. Church Island which is on the lake was the site of a pre-Viking monastery and during the summer it is normally reachable by foot. Due to the area's many rare plants and it being a stopping point for migrating birds the area was protected as the Lough Beg National Nature Reserve. It is one of the main Irish breeding areas for the scarce Garganey.