Long Island is about 130 kilometres long and 6 km wide at its widest point. The land area is 448 km². Long Island is situated about 265 km southeast of the Bahamian capital of Nassau, which is located on the island of New Providence. The Tropic of Cancer runs through the northern quarter of the island.
The northeast side of Long Island is noted for its steep rocky headlands, while the southwest coast is noted for its broad white beaches with soft sand. The terrain ranges widely throughout the island, including white flat expanses from which salt is extracted, swamplands, beaches, and sloping (in the north) and low (in the south) hills.
Long Island is particularly noted for its caves, which have played a major role in the island's history. Dean's Blue Hole, located west of Clarence Town, is the world's deepest underwater sinkhole, dropping to a depth of about 200 meters, making it more than double the depth of most other large holes.
Long Island is surrounded by small bays and inlets, including the large New Found Harbour west of Deadman's Cay, at approximately the midsection of the island. There are also smaller islands off-shore, including Sandy Cay
