Square Bay is a bay

Bay

A bay is an area of water mostly surrounded by land. Bays generally have calmer waters than the surrounding sea, due to the surrounding land blocking some waves and often reducing winds. Bays also exist as an inlet in a lake or pond. A large bay may be called a gulf, a sea, a sound, or a bight...

, roughly square in outline and 10 nautical miles (18 km) wide, indenting the west coast of Graham Land

Graham Land

Graham Land is that portion of the Antarctic Peninsula which lies north of a line joining Cape Jeremy and Cape Agassiz. This description of Graham Land is consistent with the 1964 agreement between the British Antarctic Place-names Committee and the US Advisory Committee on Antarctic Names, in...

 between Nicholl Head

Nicholl Head

Nicholl Head is a bold west extremity of the ridge separating Dogs Leg Fjord and Square Bay, on the west coast of Graham Land. First surveyed in 1936 by the British Graham Land Expedition under Rymill. Resurveyed in 1948 by the Falkland Islands Dependencies Survey and named for Timothy M....

 and Camp Point. Most of the entrance to the bay is occupied by Horseshoe Island

Horseshoe Island (Antarctica)

Horseshoe Island is an island 6.5 nautical miles long and 3 nautical miles wide occupying most of the entrance to Square Bay, along the west coast of Graham Land. Discovered and named by the British Graham Land Expedition under Rymill who mapped this area by land and from the air in 1936-37...

, which limits access to a narrow southern strait opening onto Marguerite Bay

Marguerite Bay

Marguerite Bay or Margaret Bay is an extensive bay on the west side of the Antarctic Peninsula, which is bounded on the north by Adelaide Island and on the south by Wordie Ice Shelf, George VI Sound and Alexander Island. The mainland coast on the Antarctic Peninsula is Fallières Coast. Islands...

 and a narrower northwestern strait opening onto the mouth of Bourgeois Fjord

Bourgeois Fjord

Bourgeois Fjord is an inlet, long in a northeast–southwest direction and wide, lying between the east sides of Pourquoi Pas Island and Blaiklock Island and the west coast of Graham Land. It separates Loubet Coast to the north from Fallières Coast to the south...

. Mapped and named by the British Graham Land Expedition

British Graham Land Expedition

A British expedition to Graham Land led by John Lachlan Cope took place between 1920 and 1922. The British Graham Land Expedition was a geophysical and exploration expedition to Graham Land in Antarctica between 1934 to 1937. Under the leadership of John Riddoch Rymill, the expedition spent two...

(BGLE), 1934–37, under Rymill.