44°15′N 68°27′W / 44.25°N 68.45°W
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.[1] Morgan Bay, Union River Bay, and Western Bay empty into it. Long Island in the north of the bay is the largest uninhabited island in Maine.[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.[5]