Elbow Lake is situated on approximately 400 hectares of mixed forest and wetland. Its maximum depth is approximately 10 m. As its name implies, it is elbow-shaped. It is approximately 1000 metres along its longest dimension running north to south, and about 200 metres at its widest. At its easternmost point, through a series of marshes, it joins the smaller Spectacle Lake. It does not connect to any larger lakes or to the Rideau Canal system via surface hydrology and is fed by a series of adjacent wetlands and streams. At its southern end is a small dam which helps to maintain depth.