It is part of Indiana Dunes National Park, an area that many citizens, scientists, and politicians fought hard to preserve.

Pinhook Bog is about 580 acres (2.3 km2), a quarter of which is a floating mat of sphagnum peat moss.

A bog differs from swamps, marshes, and ponds because of this limited exchange of water.

[5] The outstanding feature of Pinhook Bog is the tree-covered mat of sphagnum moss.

As the moisture becomes less acidic, typical land plants take root and the bog disappears.

[5] Orchids: Carnivorous plants:[6] Poison sumac is prevalent in the bog area, particularly around the outer edge, the "moat".

Starting at the parking lot off Wozniak Road, a leisurely trail of about 1⁄2 mile (0.80 km) leads through the woods to the entrance to the bog, which is gated and locked during non-tour hours.