The park is a trapezoid-shaped area of land enclosing Nagagamisis Lake and a jumble of other waters. It lies on a narrow peninsula extending from the south shore of Nagagamisis. Several metres offshore, the sandy beaches give way to a belt of delicate pebbles that seem to have been painstakingly sorted by the action of the waves.

Nagagamisis -- a Cree word meaning "lake with fine, sandy shores" -- owes the sandiness of its shores to the pausing of a retreating glacier, some 9000 years ago. Not only did the colossal ice-mountain pause, it reversed itself briefly, turning south and creating the Arnott Moraine before resuming its northward evacuation. This occurred just northwest of the present lake. As a result, clusters of small, irregular moraines, kames, and other glacial features are found throughout the region.

Reminders of former human activity include the remains of a trapper's cabin, two Indian graveyards, and pottery fragments indicating that nomads lived in the area for at least 1000 years. Two very different types of vegetation co-exist in the park, one in the well drained, hilly areas and the other in the lower, poorly drained areas. On the higher ground many of the trees are tall, majestic and mature. Common species are balsam, poplar, white birch, spruce, and jack pine. Ground covers in these drier areas include sarsaparilla, clintonia, bunchberry, large-leafed aster, and other vegetation. The lower, poorly drained bog areas are treed with scattered alders and tamarack, with sphagnum moss, Labrador tea, horsetails and other plants.

Moose and small mammals such as fox and beaver are present in the park. The park is also adjacent to two migratory flyways and home to loon, flicker, merlin, gray jay, merganser, and pileated woodpecker, among others.