Princess Mary Lake is a large freshwater lake situated in the Kivalliq Region of Nunavut, Canada, at coordinates 63°57′N 97°35′W. Known in Inuktitut as Tahijuaq tuklirpaar, the lake sits at an elevation of 116 m (381 ft) above sea level and covers a surface area of approximately 471 km² (182 sq mi), making it a substantial body of water by any measure. Its origin is glacial scour, which accounts for its considerable depth potential and irregular shoreline character.

The lake contains numerous islands that collectively occupy roughly 53 km² of the total surface area, offering paddlers a complex and varied environment to navigate. The Kunwak River serves as both the primary inflow and outflow, connecting the lake to the broader watershed.

The climate is classified as cold with cold summers and no distinct dry season, which defines the paddling window. Conditions are typical of the subarctic Kivalliq Region, with a short warm season and the ever-present possibility of rapid weather changes. Paddlers should plan accordingly, as the remoteness of the location means emergency assistance is not readily available. A documented wilderness canoe trip in the area involved a grizzly bear encounter, underscoring that wildlife safety — including carrying bear spray — is a serious consideration for anyone traveling in this region.

Wildlife around the lake includes caribou and foxes. Fish species documented in the broader surrounding waters include lake char (lake trout), Arctic char, and Arctic grayling, suggesting the lake and its connecting river system support cold-water fish communities typical of the region.

Given the lake's remote location in Nunavut, paddlers should expect no developed facilities or amenities. Self-sufficiency, thorough pre-trip planning, and appropriate safety equipment including satellite communication devices are essential for any expedition here.