The park is in the St. Lawrence Lowlands. It is Canada's second smallest national park, after the Georgian Bay Islands National Park. This is because it is only . A very large area of the park is marshland and has ponds. This is 70% of the park. The rest of the park is mostly forest. Forests are 21% of the park. The sandspit around the park mostly has till plains. These till plains were created in the last Ice Age.