The Indian Ocean is separated from the Atlantic Ocean by the 20° east meridian running south from Cape Agulhas, and from the Pacific Ocean by the 146°49’E meridian extending south from Tasmania’s southernmost point. The Persian Gulf lies approximately 30° north of the northernmost extent of the Indian Ocean (including marginal seas).
The entire Indian Ocean is located in the Eastern Hemisphere, and the 90th meridian east crosses across the Ninety East Ridge. In contrast to the Atlantic and Pacific, the Indian Ocean is bounded on three sides by major landmasses and an archipelago and does not reach from pole to pole.
Although the Indian Peninsula played an important role in its history, the Indian Ocean has been a cosmopolitan stage since early in human history, interconnecting disparate places through innovations, trade, and religion.
The three countries with the longest shorelines and exclusive economic zones are Australia, Indonesia, and India. The Indian Ocean’s continental shelf accounts for 15% of its total area. Countries surrounding the Indian Ocean have more than two billion people, compared to 1.7 billion for the Atlantic and 2.7 billion for the Pacific.
The largest rivers that flow into it are the Zambezi, Ganges-Brahmaputra, Indus, Jubba, and Murray.