Blue Hill Bay is a bay lying to the west of Mount Desert Island in Hancock County, Maine, United States.
[1] Approximately 14 mi (23 km) long, its southern boundaries are set by Swan's Island and Placentia Island at its entrance; the town of Blue Hill lies at the far end.
[2] Due to its protected waters, Blue Hill Bay is popular with recreational boaters.
[2] In addition to crab, lobster, and other fisheries, aquaculture of salmon and mussels is practiced in the bay.
[3][4] The shores of the bay are an important breeding ground for harbor seals.