The meridian 9° west of Greenwich is a line of longitude that extends from the North Pole across the Arctic Ocean, the Atlantic Ocean, Europe, Africa, the Southern Ocean, and Antarctica to the South Pole. The 9th meridian west forms a great circle with the 171st meridian east.

From Pole to Pole

Starting at the North Pole and heading south to the South Pole, the 9th meridian west passes through: ! scope="col" width="125" | Co-ordinates ! scope="col" | Country, territory or sea ! scope="col" | Notes ! scope="row" style="background:#b0e0e6;" | Arctic Ocean ! scope="row" style="background:#b0e0e6;" | Atlantic Ocean ! scope="row" | 🇳🇴 ! scope="row" style="background:#b0e0e6;" | Atlantic Ocean ! scope="row" | 🇮🇪 ! scope="row" style="background:#b0e0e6;" | Atlantic Ocean ! scope="row" | 🇪🇸 ! scope="row" style="background:#b0e0e6;" | Atlantic Ocean ! scope="row" | ! scope="row" style="background:#b0e0e6;" | Atlantic Ocean ! scope="row" | 🇲🇦 ! scope="row" | Western Sahara ! scope="row" | undefined ! scope="row" | undefined ! scope="row" | 🇬🇳 ! scope="row" | 🇱🇷 ! scope="row" style="background:#b0e0e6;" | Atlantic Ocean ! scope="row" style="background:#b0e0e6;" | Southern Ocean ! scope="row" | Antarctica