Great Bay is a large estuary located in the state of New Hampshire, USA. It is part of the larger Piscataqua River watershed and is known for its diverse ecosystems, including salt marshes, mudflats, and tidal rivers. The bay is an important habitat for various species of fish, birds, and other wildlife, making it a vital area for conservation efforts. The surrounding region includes several towns, such as Durham and Newmarket, which contribute to the local economy through tourism and fishing. Great Bay is also a popular spot for recreational activities like kayaking, sailing, and birdwatching, attracting nature enthusiasts year-round.