Wanderlust World Wanderlust World By surface area—the standard measure for "largest lake":
| Lake | Location | Surface Area | Notes |
|---|---|---|---|
| Lough Neagh | Northern Ireland | 392 km² (151 sq mi) | Largest in British Isles |
| Loch Lomond | Scotland | 71 km² (27 sq mi) | Largest in Scotland by area |
| Loch Ness | Scotland | 56 km² (22 sq mi) | 2nd in Scotland by area; largest by volume (7.45 km³) due to depth (230 m) |
It's 5.5× larger than Loch Lomond and 7× larger than Loch Ness by surface area.
If measuring by water volume, Loch Ness wins (7.45 km³) > Loch Lomond (2.6 km³) > Lough Neagh (3.5 km³)—because Ness is deep (230 m avg 132 m) while Lough Neagh is shallow (avg 9 m, max 25 m).
So: Largest by area = Lough Neagh. Largest by volume = Loch Ness.