| Muckno Lake | |
| Pushpin Map: | Island of Ireland |
| Pushpin Map Alt: | Muckno Lake location in Ireland |
| Pushpin Label Position: | none |
| Pushpin Map Caption: | Location in Ireland |
| Location: | County Monaghan |
| Outflow: | Clarebane River |
| Catchment: | 109.08km2 |
| Basin Countries: | Ireland |
| Length: | 3.7km (02.3miles) |
| Width: | 1km (01miles) |
| Area: | 3.57km2 |
| Depth: | 4m (13feet) |
| Max-Depth: | 20m (70feet) |
| Elevation: | 86m (282feet) |
Muckno Lake, also known as Lough Muckno, is a freshwater lake in the northeast of Ireland. It is located in County Monaghan beside the town of Castleblayney.
Muckno Lake measures about 4km (02miles) long and 1km (01miles) wide. It flows out to the Clarebane River, which connects the lake to nearby Lough Ross.
Fish species in Muckno Lake include European perch, common roach, common bream, gudgeon, northern pike and the critically endangered European eel.