The meridian 170° west of Greenwich is a line of longitude that extends from the North Pole across the Arctic Ocean, Asia, the Pacific Ocean, the Southern Ocean, and Antarctica to the South Pole.
The 170th meridian west forms a great circle with the 10th meridian east.
Starting at the North Pole and heading south to the South Pole, the 170th meridian west passes through:
| Co-ordinates | Country, territory or sea | Notes |
|---|---|---|
| Arctic Ocean | ||
| Chukchi Sea | ||
| Bering Sea | ||
| Chukotka Autonomous Okrug — Chukchi Peninsula | ||
| Bering Sea | ||
| Alaska — St. Lawrence Island | ||
| Bering Sea | Passing just east of St. Paul Island, Alaska, (at) Passing just west of St. George Island, Alaska, (at) | |
| Alaska — Carlisle Island and Chuginadak Island | ||
| Pacific Ocean | Passing just west of (at) | |
| Southern Ocean | ||
| Antarctica | Ross Dependency, claimed by | |