Great Bay is a tidal estuary in southeastern New Hampshire, part of a larger system linked to the Piscataqua River and reaching unusually far inland. Formed about 14,000 years ago as glaciers melted and rising seas flooded river valleys, it has deep channels, broad mudflats, and strong tides that expose much of the bay at low water. Its varied habitats support many species, including threatened and endangered ones, and eelgrass is especially important to the ecosystem. Native Americans first lived along its shores, and later settlers made it a busy industrial waterway. After pollution and a defeated 1973 refinery proposal, conservation became central to its modern identity.

Greenland, New Hampshire · USA