Lough Mahon

Lough Mahon Loch Machain
Location	Cork/County Cork
Coordinates
Primary inflows	River Lee, Glashaboy River, Tramore River
Primary outflows	River Lee
Basin countries	Ireland
Max. length	3 km (1.9 mi)
Max. width	5 km (3.1 mi)
Surface area	12.23 km2 (4.72 sq mi)

Lough Mahon (Irish: Loch Machain) is a sea lough situated in the north-western part of Cork Harbour. It has a total area of 12.23 km2.

Several of Cork's suburbs, such as Mahon, Douglas, Rochestown, Blackrock and Passage West are situated on its southern and western shores. To the north is Little Island and to the east Great Island.

It is regarded as the second most important bird habitat in Cork Harbour.