The Great Bog is one of the three largest wetland complexes in Seacoast New Hampshire. Within this large unfragmented area (over 600 acres) are a variety of wetland types, many upland islands, and several unique natural communities. This area makes up a significant portion of the Pickering Brook Watershed that flows to Great Bay. An additional 300 contiguous acres in the Sagamore Creek Watershed provide a total unfragmented area of nearly 900 acres that helps sustain the water resources and habitats in this area.