island in the Bolivian (eastern) sector of Lake Titicaca (Titicaca, Lake), just northwest of the Copacabana peninsula. The island, whose name is Spanish for “Island of the Sun,” was an important centre of pre-Columbian settlement in the eastern part of the Andes mountain ranges. It has an area of 5.5 square miles (14.3 square km).

The island takes its name from the Temple of the Sun, traditionally the site where Manco Capac and Mama Ocllo, the founders of the Inca dynasty, were sent to earth by the sun god. The temple was probably built by Topa Inca Yupanqui (reigned c. 1471–93), who reputedly occupied the best preserved of the island's other major sites, the Inca's Palace (or Pilco Kayma), a two-story, 50- by 43-foot (15- by 13-metre) building with galleries cut from the living stone surrounded by fountains and gardens. Other remains on the island are less well preserved, but many stone terraces, dating to Inca times, are still maintained and used for agriculture. Just to the southeast is the smaller Isla de la Luna (“Island of the Moon”), which is also the site of Inca ruins. The Cordillera Real (Real, Cordillera) can be seen from the island. Pop. (latest est.) 1,806.