The meridian 104° west of Greenwich is a line of longitude that extends from the North Pole across the Arctic Ocean, North America, the Pacific Ocean, the Southern Ocean, and Antarctica to the South Pole. The 104th meridian west forms a great circle with the 76th meridian east. In the United States, the western boundaries of North Dakota, South Dakota, and Nebraska and the eastern boundaries of Montana and Wyoming lie on the meridian 27° west of Washington, which is a couple of miles west of the meridian 104° west of Greenwich. In Colorado, the meridian 104° west of Greenwich roughly defines the eastern extent of the region of high plains protected by the Southern Rocky Mountains.

From Pole to Pole

Starting at the North Pole and heading south to the South Pole, the 104th meridian west passes through: ! scope="col" width="130" | Co-ordinates ! scope="col" | Country, territory or sea ! scope="col" | Notes ! scope="row" style="background:#b0e0e6;" | Arctic Ocean ! scope="row" | 🇨🇦 ! scope="row" style="background:#b0e0e6;" | Maclean Strait ! scope="row" | 🇨🇦 ! scope="row" style="background:#b0e0e6;" | Desbarats Strait ! scope="row" | 🇨🇦 ! scope="row" style="background:#b0e0e6;" | Byam Martin Channel ! scope="row" style="background:#b0e0e6;" | Austin Channel ! scope="row" | 🇨🇦 ! scope="row" style="background:#b0e0e6;" | Parry Channel ! scope="row" style="background:#b0e0e6;" | M'Clintock Channel ! scope="row" | 🇨🇦 ! scope="row" style="background:#b0e0e6;" | Queen Maud Gulf ! scope="row" | 🇨🇦 ! scope="row" | 🇺🇸 ! scope="row" | 🇲🇽 ! scope="row" style="background:#b0e0e6;" | Pacific Ocean ! scope="row" style="background:#b0e0e6;" | Southern Ocean ! scope="row" | Antarctica