Lough Muckno is a freshwater lake in County Monaghan, located beside the town of Castleblayney in the northeast of Ireland. The lake measures approximately 3.7 km long and 1.0 km wide, covering a surface area of around 3.57 km², with an average depth of 4 metres and a maximum depth of 20 metres. It sits at an elevation of 86 metres above sea level. The lake drains via the Clarebane River, which connects it to nearby Lough Ross.

The lake is dotted with several islands, including White Island, Black Island, and Yellow Island, which provide natural waypoints for paddlers exploring the water. A short channel beneath the Black Island Bridge connects the main lake to Gas Lake to the north, and from there paddlers can access Mindzenty Park. The shoreline and islands support varied flora and fauna, and wildlife observation is a noted feature of paddling here.

Kayak rental and group supervised paddling sessions are available through Monaghan Adventure (Castleblayney Outdoor Adventure Centre), located at Lough Muckno Park, Onomy, Castleblayney, Co. Monaghan. The centre caters to groups and offers supervised rentals, with under-18s required to be accompanied by an adult. A Trailer Café on the lake provides a stop for refreshments during outings. The Muckno Adventure Ski Club also operates on the lake, so paddlers should be aware of other water users.

Access to parts of the lake is managed, and access codes and keys for certain fishing locations can be arranged through the local tackle shop, Lakeside Angling in Castleblayney. Paddlers planning independent access should verify current arrangements in advance. The lake has hosted kayak angling events, including legs of the All Ireland Kayak Angling Championship, indicating it is well-suited to kayak-based activities.

European perch, common roach, common bream, gudgeon, northern pike, and the critically endangered European eel are fish species present in the lake. The lake is a significant coarse fishing venue and hosts local, national, and international angling competitions, which may affect paddling conditions and access at certain times of year.