Jaya Peak (both: jä´yə), mountain peak in the Sudirman Mts., Papua prov., Indonesia, on W New Guinea, rising to 16,503 ft (5,031 m). It is the highest point on New Guinea and in Indonesia and the highest island mountain in the world. The peaks are snow-covered, but the lower slopes have lush tropical vegetation. It was formerly called Mt. Carstensz and Mt. Sukarno.