Picton, Lennox and Nueva form a group of three islands at the extreme southern tip of South America, in the Chilean commune of Cabo de Hornos in Antártica Chilena Province, Magallanes and Antártica Chilena Region. Located in the Tierra del Fuego archipelago, they lie east of Navarino Island and are separated from the Argentine part of Isla Grande in the north by the Beagle Channel. They have an area of 170.4 km2 (Lennox), 105.4 km2 (Picton), 120.0 km2 (Nueva).

The Yelcho was built in 1906 by the Scottish firm Geo. Brown and Co. of Greenock, on the River Clyde for towage and cargo service of the Chilean Sociedad Ganadera e Industrial Yelcho y Palena, Puerto Montt. In 1908 she was sold to the Chilean Navy and ordered to Punta Arenas as a tug and for periodic maintenance and supply of the lighthouses in that region.