The Volcano Islands are three small islands south of the Japanese Mainland in the Pacific Ocean, named Kita-Io-to 北硫黄島, Io-to 硫黄島, and Minami-Io-to 南硫黄島. In the United States, these are usually called North Iwo Jima, Iwo Jima, and South Iwo Jima, respectively. Only Iwo Jima is populated.

The islands were unaffiliated until Japanese fishermen and entrepreneurs claimed them in the late 19th century. The islands were formally annexed in 1891. The largest island, formerly called Iwo Jima, was converted into a large military base during the inter-war period and was the scene of bloody fighting between the U.S. Marine Corps and the Imperial Japanese Army during the closing stages of the Second World War. 

Although Japan retained sovereignty over the islands following the end of the war the United States administered the islands from 1951 to 1968, when they were returned to Japan. Its name was officially changed to Io-To in 2007. The Tokyo Prefectural Government officially administers the islands on behalf of the government of Japan along with the Ogasawara (Bonin) Islands.