The meridian 78° 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.
The 78th meridian east forms a great circle with the 102nd meridian west.
Starting at the North Pole and heading south to the South Pole, the 78th meridian east passes through:
| Co-ordinates | Country, territory or sea | Notes |
|---|---|---|
| Arctic Ocean | ||
| Kara Sea | Passing just east of Vize Island, Krasnoyarsk Krai, | |
| Yamalo-Nenets Autonomous Okrug — Oleniy Island and Gydan Peninsula | ||
| Yuratski Bay | ||
| Yamalo-Nenets Autonomous Okrug — Gydan Peninsula | ||
| Khalmyer Bay | ||
| Yamalo-Nenets Autonomous Okrug — Gydan Peninsula | ||
| Taz Estuary | ||
| Yamalo-Nenets Autonomous Okrug — Gydan Peninsula | ||
| Taz Estuary | ||
| Yamalo-Nenets Autonomous Okrug Khanty-Mansi Autonomous Okrug — from Tomsk Oblast — from Novosibirsk Oblast — from Altai Krai — from | ||
Almaty Region passing through Lake Balkhash | ||
| Issyk-Kul Region passing through Issyk Kul lake | ||
| Xinjiang | ||
| Aksai Chin | Disputed between and - for about 11 km | |
| Ladakh — claimed by Himachal Pradesh — from Uttarakhand — from Uttar Pradesh — from, passing through Agra Rajasthan — from Madhya Pradesh — from Maharashtra — from Telangana — from Andhra Pradesh — from Karnataka — from Tamil Nadu — from, passing 8 km west of Madurai | ||
| Indian Ocean | ||
| Southern Ocean | ||
| Antarctica | Australian Antarctic Territory, claimed by | |