Surface Area of Lough 383km²
Average depth 8.9m
Maximum depth 30m
Volume 3.45 x 10⁹ m²
Length of shoreline approximately 125km
Maximum length 30.5km (SW-NE)
Maximum width 12.1km (W-E)
Total Lough Neagh Catchment 5750km²
LN Catchment (NI) 4450km² (31% of Northern Ireland)
LN Catchment (ROI) 390km²
LB Catchment 910km²
Total LN & LB Catchment (NI) 5360km² (38% of Northern Ireland)
Status: Hypertrophic – 145 micrograms phosphorus per litre
Blackwater, Ballinderry, Moyola, Six Mile Water, Main and Upper Bann are major tributaries, Glenavy and Crumlin are minor tributaries
Lower Bann (reaching the sea at Portstewart)
McMahon Scheme (began 1847-1858) lowered water level by 0.76m.
Shepherd Scheme (1930-1942) plus 1952 and 1959 Schemes lowered average water levels by 1.26m.
Average-to-average lowering over 160 years = 2.02m.
Area of Scientific Interest (1965) re-designated ASSI (1992)
Ramsar Site from 1976
Special Protection Area (from 1998)