Erromango is the largest island in Tafea Province, the southernmost province of Vanuatu. Its highest point is Mount Santop, at 886 m. Its largest villages are Port Narvin (Potnarvin) and Dillons Bay (Upongkor). The former main village was Ipota. The total area of Erromango is 888 km².
It was formerly known as Martyr's Island by the Presbyterian missionaries in the 19th century, because of the risk attached to missionary activity there.
John Williams of the London Missionary Society and a colleague were killed and eaten at Dillon Bay in 1839. In December 2009, after a lengthy collaboration between the Museum of Anthropology at the University of British Columbia and church and cultural leaders in Vanuatu, descendants of Williams travelled to Erromango to accept the apologies of descendants of those who killed their ancestor in a ceremony of reconciliation. To mark the occasion, Dillons Bay was renamed Williams Bay.
The Rev. George Nicol Gordon, of Prince Edward Island, Canada and his wife, Ellen Catherine Powell, missionaries from the Presbyterian Church of Nova Scotia to the New Hebrides, were massacred by the natives at Erromango on May 20th, 1861. A memoir of the couple appeared in book form, at Halifax, Nova Scotia in 1863.
The youngest volcanoes on the island are the three stratovolcanoes that form the Traitor's Head peninsula, north of Cook Bay on the eastern coast. A submarine vent between the peninsula and nearby Goat Island erupted in 1881.
Formerly it was known as a source of sandalwood in the 19th century, and much of it was depleted. It is also home to the kauri and tamanu trees. There has been extensive logging, but most of the area is recovering, and efforts are underway to try to make the industry sustainable. With European Union support, there is a protected Happy Lands Kauri Reserve.
Erromango was one of the more important sources of workers for the blackbirding crews. At one time the population of Erromango exceeded 10,000, today it is approximately 1500.
Historically there have been four languages of Erromango, Sie, Sorung, Ura, and Utaha (Ifo), but Sorung and Utaha are now extinct, and there are very few speakers of Ura. They constitute the Erromanga-language branch of South Vanuatu languages.
- "BBC News - Island holds reconciliation over cannibalism". news.bbc.co.uk. 2009-12-07. Retrieved 2009-12-07.
- Morgan, Henry James Types of Canadian women and of women who are or have been connected with Canada : (Toronto, 1903) 
- "Traitor's Head". Global Volcanism Program, Smithsonian Institution. http://www.volcano.si.edu/world/volcano.cfm?vnum=0507-09%3D.