Starting at the North Pole and heading south to the South Pole, the 121st meridian west passes through:

Co-ordinates	Country, territory or sea	Notes
90°0′N 121°0′W / 90.000°N 121.000°W / 90.000; -121.000 (Arctic Ocean)	Arctic Ocean
76°45′N 121°0′W / 76.750°N 121.000°W / 76.750; -121.000 (Canada)	Canada	Northwest Territories — Prince Patrick Island
75°44′N 121°0′W / 75.733°N 121.000°W / 75.733; -121.000 (M'Clure Strait)	M'Clure Strait
74°28′N 121°0′W / 74.467°N 121.000°W / 74.467; -121.000 (Canada)	Canada	Northwest Territories — Banks Island
71°26′N 121°0′W / 71.433°N 121.000°W / 71.433; -121.000 (Amundsen Gulf)	Amundsen Gulf
69°40′N 121°0′W / 69.667°N 121.000°W / 69.667; -121.000 (Canada)	Canada	Northwest Territories — passing through the Great Bear Lake British Columbia — from 60°0′N 121°0′W / 60.000°N 121.000°W / 60.000; -121.000 (British Columbia), passing through Tumbler Ridge
49°0′N 121°0′W / 49.000°N 121.000°W / 49.000; -121.000 (United States)	United States	Washington — passing 3 km (1.9 mi) west of Cle Elum Oregon — from 45°39′N 121°0′W / 45.650°N 121.000°W / 45.650; -121.000 (Oregon) California — from 42°0′N 121°0′W / 42.000°N 121.000°W / 42.000; -121.000 (California), passing through Modesto (at 37°38′N 121°0′W / 37.633°N 121.000°W / 37.633; -121.000 (Modesto))
35°28′N 121°0′W / 35.467°N 121.000°W / 35.467; -121.000 (Pacific Ocean)	Pacific Ocean
60°0′S 121°0′W / 60.000°S 121.000°W / -60.000; -121.000 (Southern Ocean)	Southern Ocean
73°41′S 121°0′W / 73.683°S 121.000°W / -73.683; -121.000 (Antarctica)	Antarctica	Unclaimed territory

• 120th meridian west
• 122nd meridian west