Duncan Lake in Cook County, Minnesota, is a 481-acre lake with a maximum depth of 130 feet, located within the Boundary Waters Canoe Area Wilderness. Accessed via Entry Point 60, the lake serves as a popular gateway to the remote interior of the BWCAW and is reached by paddling across the west end of West Bearskin Lake and portaging 75 rods (approximately 0.25 miles) from the parking area. The lake features seven designated campsites, though these tend to fill quickly due to the relatively easy access and proximity to the popular Stairway Portage attraction.

The portage between West Bearskin and Duncan is well-maintained and moderately challenging, with some uphill sections but manageable for beginners gaining portaging experience. Crystal-clear water typical of the region allows paddlers to see deep into the lake's depths.

Duncan Lake's defining feature is the Stairway Portage at its northern end—an 80-rod portage featuring over 120 wooden steps (replaced with stone steps in 2022) that connect to Rose Lake via the scenic Rose Falls. This 30-foot waterfall attracts numerous day-trippers, making Duncan one of the busier lakes in the BWCAW, particularly during summer weekends. Day-use permits are unlimited, so paddlers should expect to encounter other groups, especially near the Stairway Portage area.

The lake offers good fishing for lake trout and smallmouth bass, and paddlers may observe common BWCAW wildlife including loons, bald eagles, deer, and occasionally moose.

The Border Route Hiking Trail intersects the Stairway Portage, providing opportunities for those who wish to combine paddling with hiking to scenic overlooks above Rose Lake.

Due to its popularity and proximity to resorts along the Gunflint Trail, Duncan Lake is best suited for those seeking an accessible introduction to the BWCAW rather than complete solitude. Wind can create challenging conditions on the lake's open water, particularly when heading north, and afternoon westerly winds are common.