Beagle Channel is a strait in the archipelago island chain of Tierra del Fuego on the extreme southern tip of South America partly in Chile and partly in Argentina. The channel separates the larger main island of Isla Grande de Tierra del Fuego from various smaller islands including the islands of Picton, Lennox and Nueva; Navarino; Hoste; Londonderry; and Stewart. The channel's eastern area forms part of the border between Chile and Argentina and the western area is entirely within Chile.
The Beagle Channel, the Straits of Magellan to the north, and the open ocean Drake Passage to the south are the three navigable passages around South America between the Pacific and Atlantic Oceans. The Beagle Channel and the Straits of Magellan are both very narrow passages which severely limit the size and types of ships that can safely use them, hence, most commercial shipping is done through the Drake Passage.
The Beagle Channel is about 240 kilometres (130 nmi; 150 mi) long and is about 5 kilometres (3 nmi; 3 mi) wide at its narrowest point. It extends from Nueva Island in the east to Darwin Sound and Cook Bay in the west. Some 50 kilometres (27 nmi; 31 mi) from its western end it divides into two branches, north and south of Gordon Island. The southwest branch, between Hoste Island and Gordon Island, enters Cook Bay, a bay of the Pacific Ocean. The northwest branch, between Gordon Island and Isla Grande, enters Darwin Sound, which connects to the Pacific Ocean by the O'Brien Channel and the Ballenero Channel. The biggest settlement on the channel is Ushuaia in Argentina followed by Puerto Williams in Chile, two of the southernmost settlements of the world.