The lake has a surface area of and a volume of. Its maximum depth is and average depth. The shoreline is and the catchment area of the lake is. Great Bear Lake is covered with ice from late November to July. The lake is known for its considerable clarity. Explorer John Franklin wrote in 1828 that a white rag placed in the water did not disappear until it exceeded a depth of.
Arms
Arms of Great Bear Lake include the Smith Arm, the Dease Arm, the McTavish Arm, the McVicar Arm and the Keith Arm. The community of Deline is located on the Keith Arm near the outflow of the Great Bear River that flows west into the Mackenzie River at Tulita.
Tributaries
Rivers flowing into Great Bear Lake include the Whitefish River, Big Spruce River, Haldane River, Bloody River, Sloan River, Dease River and the Johnny Hoe River.
Prehistoric geology
Great Bear Lake lies between two major physiographic regions: the Kazan Uplands portion of the Canadian Shield and the Interior Plains. It was part of Glacial Lake McConnell in the pre-glacial valleys reshaped by erosional ice during the Pleistocene. Since, the lake has changed from post-glacial rebound following the ice melting. Precambrian rocks of the Canadian Shield form the eastern margin of the McTavish Arm. These rocks of the Precambrian are sedimentary and metamorphic deposits supplemented by igneous intrusions forming dikes and sills.
Climate
Human use
The Deline settlement is on the lake, near the headwaters of the Bear River. There is an ice crossing from Deline to the winter road on the far side of the Great Bear River. On 5 March 2016, a tank truck fell partway through the ice road just a few days after the government had increased the allowed maximum weight limit to on the road. The truck, which was outside of Deline and close to the community's fresh water intake, as well as a major fishing area, contained approximately of heating fuel and was one of 70 truck loads intended to resupply the community. The fuel was removed from the truck by 2 am, 8 March. Three lodges around the lake are destinations for fishing and hunting. In 1995, a lake trout was caught, the largest ever caught anywhere by angling.
The Great Bear Lake is paramount in the Délı̨nę people’s identity, laws and culture. Hence, conserving it is critical for the Délı̨nę people. ɂehtsǝ́o Erǝ́ya, a former member of the Dene peoples, is widely regarded as a prophet, making over 30 prophecies which have widely come true. His prediction for the end of times claims that, as the world dries up, the little remaining life will flock to and end on the banks of the Great Bear Lake, a lake seen as a physical beating heart to humanity. The Délı̨nę people have followed these prophecies closely, the cultural considerations being a driving force for self-governance and environmental sustainability.