Europeans only slowly became aware of the location and immensity of the lake. Peter POND learned of its general location in 1783-84, and the FUR TRADE came to the area around 1800. John FRANKLIN's expedition established FORT FRANKLIN on Keith Arm 1825-26, while John RICHARDSON surveyed the north shore. P.W. DEASE spent the winter of 1837-38 at Fort Confidence, and a geological survey was carried out by Robert BELL in 1900.
Settlement was transient until pitchblende (an ore containing radium and uranium) was discovered in 1930, and Port Radium (later Echo Bay) was established at the eastern end of McTavish Arm in 1933. Exploration and servicing were made possible by BUSH FLYING. Some of the ore used to make the atomic bombs used by the US in WWII was mined here. Exhaustive mining depleted the reserves and the mines and the community have been abandoned. Déline is the only community remaining on its shores.
The lake is well stocked with fish, including relic species thought to have moved south from the Arctic Ocean ahead of the glaciers. Commercial fishing is not allowed because of the slow regeneration of the fish in the ice-cold water. The lake's name, adopted in 1902, likely refers to the bears in the area and to the size of the lake. A more poetic explanation is that it was named for the northern constellation of stars, called Great Bear, which is reflected in its waters.