Réunionisland and department, France officially Department of Réunion , French Département de la Réunion

Of volcanic origin, Réunion consists mostly of rugged mountains in an advanced state of dissection by short torrential rivers. The west-central area contains a mountain massif with three summits exceeding 9,000 feet (2,740 metres), including the Piton des Neiges (10,069 feet). This massif is encircled by several wide basins and a series of smaller plateaus. In the eastern part of the island is an area of more recent volcanism, and in the extreme east is the mountain Le Volcan, one of whose craters, Piton de la Fournaise, has been active several times since 1925. Réunion’s coast has no good natural harbours.

Moisture-laden southeast trade winds, which dominate the weather from April to October, bring abundant annual rainfall (160–315 inches [4,000–8,000 mm]) to the south and east of the island; the north and west sides, however, have as little as 25 inches (635 mm) of rain a year. Temperatures tend to be cool for the tropics, especially at higher elevations, but in summer the lowlands are uncomfortably humid. Tropical cyclones occur frequently.