volcano in western El Salvador on the southern slope of Santa Ana. It is the most active volcano in Central America, having erupted more than 50 times since 1770. Its black symmetrical cone, which was formed by a number of eruptions over a period of 200 years, is devoid of vegetation and reaches a height of 6,004 feet (1,830 metres). During the 19th century, oceangoing sailors set their course by the continuous glow from Izalco's summit, nicknaming it the “Lighthouse of the Pacific.” The volcano derives its name from the Izalco Indians. The town of Izalco is located at the southwestern foot of the volcano.