Lake Hazen is a freshwater lake in the northern part of Ellesmere Island, Nunavut, Canada, north of the Arctic Circle. It is the largest lake north of the Arctic Circle by volume. By surface area it is third largest, after Lake Taymyr in Russia and Lake Inari in Finland. The area around the lake is a thermal oasis within a polar desert, with summer temperatures up to . The lake itself is covered by ice about ten months a year. It is fed by glaciers (most importantly Henrietta Nesmith and the Gilmour Glaciers) from the surrounding Eureka Uplands—Palaeozoic rocks north of the lake, rising up to above sea level—and drained by long Ruggles River, which flows into Chandler Fjord on the northern east coast of Ellesmere Land. The lake is flanked by the Arctic Cordillera. The lake is long and up to wide, with an area of . It stretches in a southwest-northeast direction from to . The lake is up to deep and has an estimated volume of 51.4 km3. The shoreline is long and above sea level. The lake has several islands, the largest of them being Johns Island, which is long and less than wide, also extending in a southwest-northeast direction like the lake itself. Other islands include Gatter Island, Clay Island (both close to the northeastern shore), Whisler Island, and Dyas Island (both close to the southern shore). Lake Hazen is often called the northernmost lake of Canada, but detailed maps show several smaller lakes up to more than farther north on Canada's northernmost island. Turnabout Lake is immediately northeast of the northern end of Lake Hazen. Still further north are the Upper and Lower Lakes, with Upper Dumbell Lake southwest of Alert, Canada's northernmost settlement on the coast of Lincoln Sea, Arctic Ocean. The northeastern end of Lake Hazen is southwest of Alert. The lake is part of Quttinirpaaq National Park. Artifacts of Thule civilization were discovered near Lake Hazen in 2004. Thule preceded the Inuit. In 1882, Adolphus Greely was the first European to discover the lake during his 1881–1883 expedition. Greely's base camp for the exploration was Fort Conger at the northeastern shore of Ellesmere Island, at , which was established as part of the first International Polar Year. Greely named the lake in honour of General William Babcock Hazen, who had organized the expedition. Camp Hazen was established on the northern shore