Kyushu (九州, Kyūshū^?, lit. "Nine Provinces") is the third largest island of Japan and most southwesterly of its four main islands. Its alternate ancient names include Kyūkoku (九国^?, "Nine States"), Chinzei (鎮西^?, "West of the Pacified Area"), and Tsukushi-no-shima (筑紫島^?, "Island of Tsukushi"). The historical regional name is Saikaidō (西海道^?, lit. West Sea Circuit) referred to Kyushu and its surrounding islands.

In the 8th century Taihō Code reforms, Dazaifu was established as a special administrative term for the region.

As of 2006, Kyushu has a population of 13,231,995 and covers 35,640 square kilometres (13,760 sq mi).

The island is mountainous, and Japan's most active volcano, Mt Aso at 1,591 metres (5,220 ft), is on Kyushu. There are many other signs of tectonic activity, including numerous areas of hot springs. The most famous of these are in Beppu, on the east shore, and around Mt. Aso, in central Kyushu.

The name Kyūshū comes from the nine ancient provinces of Saikaidō situated on the island: Chikuzen, Chikugo, Hizen, Higo, Buzen, Bungo, Hyūga, Osumi, and Satsuma.