The Beagle Channel is a strait separating the islands of the Tierra del Fuego archipelago, in South America. It separates Isla Grande de Tierra del Fuego from several smaller islands to the south. Its eastern portion is part of the border between Chile and Argentina, but the western part is completely within Chile. The Beagle Channel is about 270km long and is about 5km wide at its narrowest point. To the west the Darwin Sound connects it to the Pacific Ocean. Although it is navigable by large ships, there are safer waters to the south (Drake Passage) and to the north (Strait of Magellan). Several small islands, Picton, Lennox and Nueva, near the eastern end, were the subject of a long-running territorial dispute between Chile and Argentina; by the terms of a 1984 treaty they are now part of Chile whilst Argentina has most maritime rights. The biggest settlement on the channel is Ushuaia in Argentina followed by Puerto Williams in Chile.