The landscape can be divided into four primary sections, each with its own unique geological features and wildlife habitats and vegetation. At the southern and western boundaries, the Caribou and Birch Uplands rise over 500 metres, sedimentary rock of the Cretaceous age, covered in spruce and lichen tundra. The eroding slopes have in some areas yielded a great density of fossils.

The Alberta plateau, the largest section of the park, is a vast wild plain spread with countless bogs, forests, meandering streams, spongy muskeg and huge silty rivers. Known as the karstland, the caves and sinkholes across the landscape dramatically demonstrate the effects of groundwater dissolving pockets of soluble gypsum bedrock. When the roof of a cave, carved out by water action on bedrock collapses, a bowl-shaped sinkhole appears, sometimes with a pond at its base. Another type, the solution sinkhole, is created when surface water seeps into cracks to dissolve underlying bedrock. Fish in the sinkholes have traveled there from streams in an underground waterway. The Slave River Lowlands along the eastern border mark the end of the boreal plains at the edge of the Canadian Shield. Springs that seep out of the surface here carry mineral salt deposits which are strewn in sheets and piles of salt across the 250 square kilometre salt plain unique to Canada. Several plant species that require a saline environment grow here far from marine shorelines. The fourth section, the Peace-Athabasca Delta, one of the largest fresh-water deltas in the world, is located in the park's southeast corner where the Peace, Athabasca, Slave and Birch Rivers flow toward the Great Slave Lake. The silt carried by these rivers remains in the delta creating a wetland of over 4800 square kilometres of biologically productive shallow lakes, marshes, grasslands and forests, a nesting and staging area for waterfowl, a spawning ground for fish and home to many animal species.