Hachiōji (八王子市, Hachiōji-shi) is a city located in the western portion of the Tokyo Metropolis, Japan. As of 31 March 2021, the city had an estimated population of 561,344, and a population density of 3,000 persons per km. The total area of the city is 186.38 km (71.96 sq mi). It is the most populous city in Tokyo outside of the special wards.

Hachiōji is located in the foothills of the Okutama Mountains of western Tokyo, about 40 kilometers west of the center of the 23 special wards of Tokyo. The city is surrounded on three sides by mountains, forming the Hachioji Basin which opens up toward the east in the direction of Tokyo. The mountain ranges in the southwest include Mount Takao (599 m) and Mount Jinba (857 m), two popular hiking destinations which can be reached by train and bus, respectively.

Kanagawa Prefecture

• Sagamihara

Tokyo Metropolis

• Akiruno
• Akishima
• Fussa
• Hino
• Hinohara
• Machida
• Tama

Hachiōji has a humid subtropical climate (Köppen Cfa) characterized by warm summers and cool winters with light to no snowfall. The average annual temperature in Hachiōji is 13.9 °C. The average annual rainfall is 1998 mm with September as the wettest month. The temperatures are highest on average in August, at around 25.3 °C, and lowest in January, at around 2.4 °C.

Per Japanese census data, the population of Hachiōji has recently plateaued after nine decades of strong growth.

Historical population

Year	Pop.	±%
1920	78,705	—
1930	95,389	+21.2%
1940	111,028	+16.4%
1950	131,470	+18.4%
1960	164,622	+25.2%
1970	253,407	+53.9%
1980	387,178	+52.8%
1990	466,347	+20.4%
2000	536,046	+14.9%
2010	580,053	+8.2%
2020	579,355	−0.1%

The area of present-day Hachiōji was part of ancient Musashi Province. It has been an important junction point and post town along the Kōshū Kaidō, the main road that connected the historical Edo (today's Tokyo) with western Japan. Hachiōji Castle was built during the Sengoku period in 1584 by Hōjō Ujiteru, but was destroyed in 1590 by Toyotomi Hideyoshi. During the Edo period, the area was tenryō controlled directly by the Tokugawa shogunate. In the post-Meiji Restoration cadastral reform of July 22, 1878, the area became part of Minamitama District in Kanagawa Prefecture. The town of Hachiōji was created on April 1, 1889, with the establishment of the modern municipalities system. Minaitama District was transferred to the administrative control of Tokyo Metropolis on April 1, 1893. Hachiōji gained city status on September 1, 1917.

During the 1964 Summer Olympics, the city played host to the road cycling events. A velodrome in the city played host to the track cycling events.

Hachiōji became a Core city on April 1, 2015 with increased local autonomy.

Hachiōji has a mayor-council form of government with a directly elected mayor and a unicameral city council of 40 members, whose members are elected for a four-year term. Hachiōji contributes five members to the Tokyo Metropolitan Assembly. In terms of national politics, the city is divided between the Tokyo 21st district and Tokyo 24th district of the lower house of the Diet of Japan.

During the Meiji period, Hachiōji prospered as an important location for the production of silk and silk textiles. The industry faded away, however, in the 1960s. Today, Hachiōji mainly serves as a commuter town for people working in Tokyo, and as a location for many large colleges and universities.

• Chuo University (Tama Campus)
• Digital Hollywood University
• Kogakuin University (Hachioji Campus)
• Kyorin University (Hachioji Campus)
• Meisei University (Hino Campus)
• Nihon Bunka University
• Soka University
• Tama Art University (Hachioji Campus)
• Takushoku University (Hachioji Campus)
• Teikyo University (Hachioji Campus)
• Tokyo Junshin University
• Tokyo Kasei-Gakuin University (Machida Campus)
• Tokyo Metropolitan University (Minamiōsawa Campus)
• Tokyo University of Agriculture and Technology
• Tokyo University of Pharmacy and Life Sciences
• Tokyo University of Technology (Hachiōji Campus)
• Tokyo Zokei University
• Nippon Engineering College
• Hachioji Municipal Nursing College [ja]

The Tokyo Metropolitan Government Board of Education operates nine public high schools, and the Hachioji School for the Blind. There are also eleven private high schools.

Metropolitan high schools:

Hachiōji has 70 public elementary schools and 37 public junior high schools operated by the city government, as well as four public combined elementary/junior high schools.

Combined public elementary and junior high schools:

• Izumi no Mori School (いずみの森義務教育学校)
• Tate (館小中学校)

Municipal junior high schools:

Municipal elementary schools:

Former:

• Takaosan Gakuen (高尾山学園) - Elementary and junior high

JR East - Chūō Main Line

• Hachiōji – Nishi-Hachiōji – Takao

JR East - Yokohama Line

• Hachiōji-Minamino – Katakura – Hachiōji

JR East - Hachikō Line

• Hachiōji – Kita-Hachiōji – Komiya

Keio Corporation - Keiō Line

• Naganuma – Kitano – Keiō-Hachiōji

Keio Corporation - Keiō Takao Line

• Kitano – Keiō-Katakura – Yamada – Mejirodai – Hazama – Takao – Takaosanguchi

Keio Corporation - Sagamihara Line

• Keiō-Horinouchi – Minami-Ōsawa

Tokyo Tama Intercity Monorail - Tama Toshi Monorail Line

• Chūō-Daigaku-Meisei-Daigaku – Ōtsuka-Teikyō-Daigaku – Matsugaya
• Takaotozan Railway

• Ken-Ō Expressway
• Chūō Expressway
• National Route 16
• National Route 20
• National Route 411

• Kaohsiung, Taiwan, friendship city since November 1, 2006
• Siheung, Gyeonggi Province, South Korea, friendship city since November 7, 2006
• Tai'an, Shandong, People's Republic of China, friendship city since September 23, 2006

Hachioji stretches over a large area, combining such diverse parts as the densely populated city center and its shopping district with the hardly populated rural areas in the west.

• Mt. Takao (599 m) is a popular hiking destination in the southwest, easily accessible through the Keiō Takao Line. It is famous for the Shingon Buddhist temple Takao-san Yakuōin Yūkiji (高尾山薬王院有喜寺).
• Mt. Jinba (855 m) is more difficult to reach, requiring a one-hour bus ride from the city center. It is popular, however, because of the scenic view toward Mt. Fuji.
• Tama Forest Science Garden
• Tokyo Fuji Art Museum
• Kamiyugi Park Baseball Field
• Kamiyugi Park Athletic Stadium
• Musashi Imperial Graveyard houses the remains of the Taishō and Shōwa emperors.
• Takiyama Castle, A castle ruin in the Sengoku period, one of the Continued Top 100 Japanese Castles.
• Hachiōji Castle, A castle ruin in the Sengoku period, one of Japan's Top 100 Castles.

• 
  Mt. Takao
• 
  Shōwa emperor's grave
• 
  Taishō emperor's grave
• 
  Reconstructed bridge of Takiyama Castle
• 
  Stone wall and gate of Hachiōji Castle

• Hachiōji City Official Website (in Japanese)