| Portmore Lough | |
| Location: | County Antrim, Northern Ireland |
| Coordinates: | 54.5667°N -21°W |
| Type: | lough |
| Pushpin Map: | Northern Ireland |
| Pushpin Label Position: | none |
| Pushpin Map Alt: | Location in Northern Ireland |
| Pushpin Map Caption: | Location in Northern Ireland |
Portmore Lough is a small lake in southwest County Antrim, Northern Ireland that drains water into nearby Lough Neagh. It is roughly circular and covers an area of . The Lough and its shoreland is designated a Ramsar site, a Special Protection Area (SPA) and an Area of Special Scientific Interest (ASSI).[1] The lough is now part of a Royal Society for the Protection of Birds nature reserve.[2]
The lough is near the site of the former Portmore Castle, erected in 1664 and removed in 1761.[3] It is also the presumed location of the Portmore Ornament Tree whose demise in a windstorm of 1760 is lamented in the Irish folk song, Bonny Portmore.[4]
Portmore Lough has the alternative name Lough Beg (Loch Bheag, or "small lake"), not to be confused with the Lough Beg on the Lower Bann.