Duncan Lake is a 130-acre lake located in Barry County, Michigan, within the Thornapple River Watershed. This inland lake reaches depths of approximately 55 feet and serves as part of the Duncan Creek subwatershed, which drains into the larger Thornapple River system. The lake supports a diverse fishery including Northern Pike, Sunfish, Yellow Perch, and other warm-water species, making it a destination for anglers as well as paddlers. The moderate size of Duncan Lake makes it accessible for kayakers and canoeists seeking a peaceful day paddle without the extended commitment required by larger water bodies.

Duncan Lake is situated in the largely rural landscape characteristic of Barry County, where over half the land use is agricultural and significant forested areas remain. This rural setting provides paddlers with scenic views of natural shorelines interspersed with seasonal and year-round residences. The lake lies within a region that experienced considerable residential development in the 1990s and early 2000s, though it has maintained much of its natural character.

Access to Duncan Lake is available via a public boat launch on Duncan Creek, which flows through the area. Paddlers should be aware that like many inland lakes in the region, Duncan Lake may contain submerged stumps and trees—remnants from when the Thornapple River was impounded—that lurk just below the surface in certain areas.

The lake's location within the Thornapple River Watershed means it benefits from the same rural character that defines much of this 422,545-acre drainage system. Wildlife viewing opportunities include white-tailed deer, various waterfowl species including blue and green herons, and potentially bald eagles, which have been documented in the broader watershed area. Water quality concerns in the watershed include nutrient loading and sediment from agricultural sources, though Duncan Lake itself provides opportunities for quiet-water paddling in a predominantly natural setting.