The climate of the archipelago is tropical marine; it is hot and humid, moderated by trade winds. The terrain is flat and low, with most areas not exceeding an elevation of . The highest point is an unnamed point on the island of Diego Garcia, at elevation, and the lowest point is the Indian Ocean.
Diego Garcia is the largest and most southern island, which occupies a strategic location in the middle of the Indian Ocean. This island is the site of a joint UK-US military facility.