The Bonin Islands, also known as the Ogasawara Islands (小笠原群島, Ogasawara Guntō), are an archipelago of over 30 subtropical and tropical islands, some 1,000 kilometres (540 nmi; 620 mi) directly south of Tokyo, Japan and 1,000 miles (870 nmi; 1,600 km) northwest of Guam. The name "Bonin Islands" comes from the Japanese word bunin (an archaic reading of 無人 mujin), meaning "no people" or "uninhabited". The only inhabited islands of the group are Chichijima (父島), the seat of the municipal government, and Hahajima (母島). Archeological evidence has revealed that some of the islands may have been prehistorically inhabited by members of an unknown Micronesian ethnicity.