Hachijō Subprefecture (八丈支庁, Hachijō-shichō) is a subprefecture of Tokyo Metropolis, Japan. The organization of government belongs to the Tokyo Metropolitan Government Bureau Of General Affairs.

The subprefecture has an area of 78.6 square km. It is located within the Izu Islands and is 200km away from Mainland Japan.

Romanji	Kanji	Area (Km²)	Population	Type	Island(s)	Map
Hachijō	八丈町	72.24	7,056	Town	Hachijō-jima and Hachijō-kojima
Aogashima	青ヶ島村	5.96	169	Village	Aogashima

Additionally, Hachijō includes the four southernmost Izu Islands, which are uninhabited. These islands currently do not belong to any municipality; both Hachijō and Aogashima claim administrative rights. From north to south, the islands are:

• Bayonnaise Rocks (Beyonēzu Retsugan)
• Smith Island (Sumisu-tō)
• Tori-shima
• Lot's Wife (Sōfu-iwa)

Among the islands of the subprefecture, only Hachijōjima and Aogashima are inhabited.

In 2023, Hachijō Subprefecture had a population of 8,790. The village of Aogashima is the least populated municipality in all of Japan, with only 169 residents

The Hachijō language, also called Shima Kotoba, is spoken exclusively on the two main islands. It is an endangered language, with 0 native speakers being children or young adults.

33°06′36″N 139°47′21″E / 33.109916°N 139.789056°E / 33.109916; 139.789056