|Native name: Islas Ildefonso|
|Adjacent bodies of water||Pacific ocean|
|Total islands||9 islands and islets|
|Area||0.2 km2 (0.077 sq mi)|
|Commune||Cabo de Hornos|
Islas Ildefonso are a group of islands in Chile. The islands belong to the Commune of Cabo de Hornos in Antártica Chilena Province of Magallanes and Antártica Chilena Region. They lie 96 km (60 mi) west of Isla Hermite, part of Tierra del Fuego, and 93 km (58 mi) NNW of Diego Ramirez Islands, but only 27 km (17 mi) south of Isla Hoste or 23 km (14 mi) to rocks near Isla Hoste.
The islands were named by the Spanish navigator Diego Ramírez de Arellano, who piloted the Garcia de Nodal expedition through the region in 1619. The islands consist of nine stacks, within two groups. They extend 6 km (4 mi) on a northwest-southeast axis. The land area measures about 200,000 m2 (2,152,782 sq ft). More than 50% of this comprises the large single southern stack, which is 970 m (3,182 ft) long and between 80 to 200 m (262 to 656 ft) wide. The islands are steep and rocky, and covered in tussac grass.
Important Bird Area
The islands have been identified by BirdLife International as an Important Bird Area because they hold large breeding populations of both southern rockhopper penguins (86,000 breeding pairs) and black-browed albatrosses (47,000 breeding pairs). There are also smaller numbers of grey-headed albatrosses. Magellanic penguins, imperial shags and sooty shearwaters present.
- List of islands of Chile
- List of Antarctic and sub-Antarctic islands
- List of Antarctic islands north of 60° S
- "Diego Ramírez de Arellano i el seu Reconosimiento de los Estrechos de Magallanes y de San Viçente". Institució Alfons el Magnànim. 4 December 2011. Retrieved 4 September 2012.
- Shirihai, Hadoram. (2002). A complete guide to Antarctic wildlife. ISBN 951-98947-0-5
- BirdLife International. (2012). Important Bird Areas factsheet: Islas Ildefonso. Downloaded from http://www.birdlife.org on 2012-01-15.