Pinhook Bog

Pinhook Bog is a unique bog in Indiana that has been designated a National Natural Landmark. It is part of Indiana Dunes National Park, an area that many citizens, scientists, and politicians fought hard to preserve. Its sister bog, Volo Bog, is located nearby. The bog contains a large variety of plants, including insect eating plants, tamarack trees, stands of blueberry bushes, and floating mats of sphagnum moss. Pinhook Bog is about , a quarter of which is a floating mat of sphagnum peat moss. A "moat" separates the bog from the uplands.
Geology.
The bog is a glacial kettle. At the end of the Wisconsin Glacial epoch about 14,000 to 15,000 years ago, a large chunk of ice remained buried at this location as the ice retreated northward. When the ice melted, the clay soil sealed the basins.
Precipitation and runoff from higher ground around the bog are the only water sources. There is no stream or groundwater inflow or outflow. Evaporation from the open water and plants is the only loss of moisture. A bog differs from swamps, marshes, and ponds because of this limited exchange of water. The water in the bog is stagnant, acidic, and nutrient-poor.
Plants.
The outstanding feature of Pinhook Bog is the tree-covered mat of sphagnum moss. Sphagnum moss is a stringy, delicate moss of a light-green color. The mat floats on top of the water and can become thick, yet it can have a pocket only a few inches thick in the middle. As the mat thickens, larger and larger plants take root and grow. Under the mat a peat bed develops. The acidic water slows the decay of the sphagnum moss and other plants. With time, the peat may fill the bog from the mat to the bottom. As the moisture becomes less acidic, typical land plants take root and the bog disappears.
Orchids: 
Carnivorous plants:
Poison sumac is prevalent in the bog area, particularly around the outer edge, the '"moat". It is recognized by its compound leaves of seven to thirteen leaflets. The leaflets have smooth edges and are pointed.
Tamarack or American larch is an unusual tree for northwest Indiana. It is a conifer, but not an evergreen. It drops its leaves in the winter. As fall approaches, the needles turn golden until they fall off.
Blueberry and cranberry shrubs are common along the margins. Rusty cotton grass farther down the trail flourishes. 
Access.
The Pinhook Bog is open for specially scheduled ranger-guided tours and for infrequent open houses. From the parking lot off Wozniak Road, a leisurely trail of about 1/2 mile leads you through the woods to the entrance to the bog, which is gated and locked during non-tour hours. Within the bog, you can walk along a plastic boardwalk which is about 1/4 mile long. You are not allowed to step on the bog as it damages the fragile ecosystem. Make sure to pay close attention to the carnivorous plants on the bog surface near the entrance - some are quite small and delicate and can be easy to miss.