The Greater Tokyo Area is the most populous metropolitan area in the world, consisting of the Kantō region of Japan (including Tokyo Metropolis and the prefectures of Chiba, Gunma, Ibaraki, Kanagawa, Saitama, and Tochigi) as well as the prefecture of Yamanashi of the neighboring Chūbu region.

Some definitions are clearly defined by law or government regulation, some are based coarsely on administrative areas, while others are for research purposes such as commuting patterns or distance from Central Tokyo.

Notes and sources: All figures issued by Japan Statistics Bureau,[11][12] except for Metro Employment Area, a study by Center for Spatial Information Service, the University of Tokyo.

Using the "One Metropolis Three Prefectures" definition, Tokyo is 13,555.65 square kilometres (5,233.87 sq mi), a similar size to that of Los Angeles County, and almost two-thirds smaller than the combined statistical area of New York City, at 30,671 square kilometres (11,842 sq mi) and 21.9 million people.

[citation needed] (populations listed for those over 300,000) Tokyo is legally classified as a to (都), which translates as "metropolis", and is treated as one of the forty-seven prefectures of Japan.

Western Tokyo, known as the Tama Area (Tama-chiiki 多摩地域) comprises a number of municipalities, including these suburban cities: The core cities of the Greater Tokyo Area outside Tokyo Metropolis are: The other cities in Chiba, Kanagawa and Saitama Prefectures are: source: stat.go.jp census 2005 In the major metropolitan area (MMA) definition used by the Japanese Statistics Bureau, the following cities in Ibaraki, Tochigi, Gunma, Yamanashi, and Shizuoka Prefectures are included: Tighter definitions for Greater Tokyo do not include adjacent metropolitan areas of Numazu-Mishima (approx.

Along the periphery of the main urban area are numerous new suburban housing developments such as the Tama New Town.

Stations are designed to accommodate hundreds of thousands of passengers at any given time, with miles of connecting tunnels linking vast department stores and corporate offices.

Greater Tokyo's Railway Network is easily considered the world's largest in terms of both daily passenger throughput with a daily trips of over 40 million (20 million different passengers) as well as physical extent with approximately 2,578 kilometres (1,602 mi) of track.

The Tokyo Monorail provides an important shuttle service between Haneda Airport and Hamamatsucho station on the Yamanote line.

Tokyo and Yokohama are major commercial seaports, and both the Japan Maritime Self-Defense Force and United States Navy maintain naval bases at Yokosuka.