It has an area of 1,437 square kilometres (555 sq mi), and mostly consists of mountainous regions, covered by rain forests.

The highest peak at 6,801 feet (2,073 metres) near Wadalei in the north-east of Fergusson Island is an extinct volcano.

Gold deposits at Wapolu on the north coast were worked briefly in the mid-1990s.

The island was named by Captain John Moresby after Sir James Fergusson, who was Governor-General of New Zealand from 1873 to 1874.

On June 30, 1942, during World War II, a United States Navy PT-Boat base was established on the island.