Neagh, Lough (lŏkh nā) [key], lake, 153 sq mi (396 sq km), 18 mi (29 km) long and 11 mi (18 km) wide, central Northern Ireland. This shallow lake is the largest freshwater body in the British Isles. Fed by the Upper Bann, Blackwater, and other streams and drained to the north by the Lower Bann, it has pollan, trout, and eel fisheries. Mesolithic humans are believed to have first appeared in Ireland (c.6000 B.C.) near the lake. According to a legend, quoted by Giraldus Cambrensis, the Norman-Welsh historian, and cited in Thomas Moore's "Let Erin Remember" ( Irish Melodies ), the lake occupies the site of a flooded town; buildings may sometimes be seen through the water.