The northwest branch between Gordon Island and Isla Grande enters Darwin Sound, which connects to the Pacific Ocean by the O'Brien and Ballenero channels.

[4] The Beagle Channel is between islands covering a much larger area; to the north lies Argentine-Chilean Isla Grande de Tierra del Fuego, to the south Hoste, Navarino, and Picton and Nueva, which were claimed by Argentina until 1984.

[5] According to a Selk'nam myth the channel was created alongside the Strait of Magellan and Fagnano Lake in places where slingshots fell on earth during Taiyín's fight with a witch who was said to have "retained the waters and the foods".

[6] The channel was named after the ship HMS Beagle during its first hydrographic survey of the coasts of the southern part of South America which lasted from 1826 to 1830.

The ship continued the survey in the second voyage of Beagle under the command of captain FitzRoy, who took Charles Darwin along as a self-funding supernumerary, giving him opportunities as an amateur naturalist.

As a ship's painter, Conrad Martens drew and created watercolour paintings in 1833 and 1834 during the second voyage of HMS Beagle in Tierra del Fuego.