The meridian 173° 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 173rd meridian west forms a great circle with the 7th meridian east.
Starting at the North Pole and heading south to the South Pole, the 173rd meridian west passes through:
| Co-ordinates | Country, territory or sea | Notes |
|---|---|---|
| Arctic Ocean | ||
| Chukchi Sea | ||
| Chukotka Autonomous Okrug — Chukchi Peninsula | ||
| Bering Sea | ||
| Alaska — St. Matthew Island | ||
| Bering Sea | ||
| Alaska — Amlia Island | ||
| Pacific Ocean | Passing just west of the island of Savai'i, (at) | |
| Southern Ocean | ||
| Antarctica | Ross Dependency, claimed by | |