Duncan Lake is located in the taiga wilderness of the Northwest Territories, approximately 15 to 20 minutes by floatplane northeast of Yellowknife. It sits within a landscape where roughly 20 percent of the surrounding area is water, interspersed with boreal forest, exposed Canadian Shield rock, and isolated islands. The lake connects with Graham Lake, and together they form the hub of a remote wilderness area accessible only by air.

The lake is well suited to flat-water canoeing and kayaking. The shoreline features imposing boulders and rocky outcroppings typical of the Canadian Shield, and the surrounding forest can be explored on foot from various landing points along the shore. The area supports a range of wildlife, including beavers, otters, and muskrats along the banks, as well as waterfowl. The waters hold lake trout, northern pike, walleye, and Arctic grayling.

Yellow Dog Lodge operates on Duncan and Graham Lakes and serves as the primary base for paddling activity in the area. The lodge offers guided canoeing and kayaking excursions, and guests can also rent a motorized tented barge for multi-day trips, allowing paddlers to anchor at different points around the lake. The lodge also provides access to five additional nearby lakes for day trips. Facilities at the lodge include private cabins, a sauna, and a wood-fired hot tub.

The operating season for the lodge runs from June 1 through September 30, which reflects the practical paddling window for the lake. The midnight sun is a notable feature during summer months, while the northern lights become visible later in the fall and in early spring, with August and September cited as particularly good months for aurora viewing. Access to the lake is exclusively by floatplane from Yellowknife, meaning there are no road-accessible put-in points.