The meridian 90° east of Greenwich is a line of longitude that extends from the North Pole across the Arctic Ocean, Asia, the Indian Ocean, the Southern Ocean, and Antarctica to the South Pole. It is the border between two tropical cyclone basins: the Australian region and the Southwest Indian Ocean basin. The Ninety East Ridge is named after the meridian. The 90th meridian east forms a great circle with the 90th meridian west. This meridian is halfway between the Prime meridian and the 180th meridian and the center of the Eastern Hemisphere is this meridian's intersection with the Equator.

From Pole to Pole

Starting at the North Pole and heading south to the South Pole, the 90th meridian east passes through: ! scope="col" width="120" | Co-ordinates ! scope="col" | Country, territory or sea ! scope="col" | Notes ! scope="row" style="background:#b0e0e6;" | Arctic Ocean ! scope="row" style="background:#b0e0e6;" | Kara Sea ! scope="row" | 🇷🇺 ! scope="row" style="background:#b0e0e6;" | Kara Sea ! scope="row" | 🇷🇺 ! scope="row" | 🇲🇳 ! scope="row" | ! scope="row" | 🇧🇹 ! scope="row" | 🇮🇳 ! scope="row" | 🇧🇩 ! scope="row" style="background:#b0e0e6;" | Indian Ocean ! scope="row" style="background:#b0e0e6;" | Southern Ocean ! scope="row" | Antarctica ! scope="row | Antarctica