# Koshigaya
**Koshigaya** (越谷市, Koshigaya-shi) is a city in southeastern [Saitama Prefecture](https://www.edgepedia.org/saitama-prefecture), [Japan](https://www.edgepedia.org/japan-epzdpsev89), lying within 25 kilometers of central [Tokyo](https://www.edgepedia.org/tokyo-ep6jg0kyrw) and functioning as a growing residential suburb of the capital.[1](https://www.city.koshigaya.saitama.jp/citypromotion/oshiete/gaiyo/) With a population of about 340,000, it is one of the largest municipalities in the prefecture, and its low-lying, river-crossed terrain has shaped both its historic identity as a "water country" (水郷こしがや, suigō Koshigaya) and its modern approach to flood management.[1](https://www.city.koshigaya.saitama.jp/citypromotion/oshiete/gaiyo/) • [2](https://www.koshigaya.city/p/about.html)
| Key fact | Detail |
|---|---|
| Location | Southeastern Saitama Prefecture, within 25 km of central Tokyo[1](https://www.city.koshigaya.saitama.jp/citypromotion/oshiete/gaiyo/) |
| Area | 60.24 km², extending 8.6 km east to west and 11.5 km north to south[1](https://www.city.koshigaya.saitama.jp/citypromotion/oshiete/gaiyo/) |
| Population | 341,059 people in 166,413 households as of 1 October 2026; about 340,000 and 4th of 63 Saitama municipalities as of 1 January 2024[3](https://www.city.koshigaya.saitama.jp/) • [1](https://www.city.koshigaya.saitama.jp/citypromotion/oshiete/gaiyo/) |
| Founding | Formed 3 November 1954 from 2 towns and 8 villages; city status 3 November 1958, the 22nd city in Saitama and 543rd nationwide, with a population of 48,318[4](https://adeac.jp/koshigaya-city-digital-archives/texthtml/d000060/mp001930-100020/ht000040) |
| Rivers | Five Class-A rivers (Motoarakawa, Furutonegawa, Ayasegawa, Niigatagawa, Nakagawa) plus irrigation channels such as the Kasai and Sueda canals[2](https://www.koshigaya.city/p/about.html) |
| Railways | JR Musashino Line east to west; Tobu Isesaki Line north to south; eight stations in the city[2](https://www.koshigaya.city/p/about.html) |
| Signature project | Koshigaya Lake Town, an approximately 230 ha development combining housing with a large flood-control reservoir[5](https://www.ur-net.go.jp/overseas/achievements/koshigaya.html) |
## Geography and character
Koshigaya occupies flat alluvial land in the southeastern corner of Saitama Prefecture, bordered by [Kasukabe](https://www.edgepedia.org/kasukabe) to the north, Matsubu and Yoshikawa to the east, Soka to the south, and Kawaguchi and Saitama City to the west.[6](https://www.sarfic.or.jp/?interview=interview-1397) The terrain is level throughout, which the city presents as an advantage for daily life by bicycle.[1](https://www.city.koshigaya.saitama.jp/citypromotion/oshiete/gaiyo/) Housing and commercial districts cluster around the railway stations, while quieter farmland remains at the city's edges.[1](https://www.city.koshigaya.saitama.jp/citypromotion/oshiete/gaiyo/)
**A landscape made by water.** The city sits between the Musashino and Shimosa plateaus, with the Ayasegawa on its western edge, the Motoarakawa through its center, and the Furutonegawa on its eastern boundary.[4](https://adeac.jp/koshigaya-city-digital-archives/texthtml/d000060/mp001930-100020/ht000040) Together with the Niigatagawa and Nakagawa, these are Class-A rivers, and irrigation channels including the Kasai, Sueda, and Yakota waterways cross the city; this abundance of water earned Koshigaya its old name of "Suigo Koshigaya," the water country.[2](https://www.koshigaya.city/p/about.html) The land itself was formed as rivers flowing into a former inlet of [Tokyo Bay](https://www.edgepedia.org/tokyo-bay) deposited sediment as the sea retreated, and settlement grew on the natural levees along the rivers while rice cultivation spread across the wetlands behind them.[4](https://adeac.jp/koshigaya-city-digital-archives/texthtml/d000060/mp001930-100020/ht000040)
The same geography carries risk. The region is a low-lying wetland traversed by major rivers including the Tone, Edogawa, and Arakawa, and the city publishes flood and inland-water hazard maps; its flood hazard map is based on a scenario in which the Tone River overflows under rainfall of 491 mm over 72 hours.[7](https://www.city.koshigaya.saitama.jp/anzen_anshin/bosai/kasenchisui/kkhm.html) • [8](https://www.city.koshigaya.saitama.jp/anzen_anshin/bosai/kasenchisui/naisuihazardmap.html)
## History
Settlement in the Koshigaya area is estimated, from artifacts recovered at the Mita-kata dwelling site excavated in the 1960s, to have begun sometime between the Kofun and Nara periods.[4](https://adeac.jp/koshigaya-city-digital-archives/texthtml/d000060/mp001930-100020/ht000040) In the medieval period the area belonged to the Niigata estate, and more than 200 memorial stone stupas (itabi) have been confirmed there, beginning with one dated 1249.[4](https://adeac.jp/koshigaya-city-digital-archives/texthtml/d000060/mp001930-100020/ht000040) Under Tokugawa rule from 1590, wetlands were drained and new rice fields opened, and by the end of the early modern period the Koshigaya region counted 2 towns and 49 villages.[4](https://adeac.jp/koshigaya-city-digital-archives/texthtml/d000060/mp001930-100020/ht000040) The city's own historical account also records that it flourished as a post town on the Nikko Kaido highway.[9](https://www.city.koshigaya.saitama.jp/kurashi_shisei/shisei/shingikai/sougou/jichikihonjoreishingi/jichi_tousin_090330_files_tousin_zentaiban_090330.pdf)
**Modern growth.** Under the postwar municipal merger promotion law, Koshigaya Town was created on 3 November 1954 by consolidating Koshigaya, Osawa, and eight other towns and villages; after further boundary changes its area reached 59.73 km².[4](https://adeac.jp/koshigaya-city-digital-archives/texthtml/d000060/mp001930-100020/ht000040) On 3 November 1958 the town was elevated to city status, the 22nd in Saitama Prefecture and the 543rd in Japan, with a population of 48,318.[4](https://adeac.jp/koshigaya-city-digital-archives/texthtml/d000060/mp001930-100020/ht000040) Population then rose in steps: past 200,000 in September 1976, past 250,000 in May 1985, and past 300,000 in December 1996, when Koshigaya became the sixth city in the prefecture to reach that mark.[2](https://www.koshigaya.city/p/about.html) On 1 April 2003 it was designated a special city (tokurei-shi), a category granting expanded municipal authority.[2](https://www.koshigaya.city/p/about.html)
Railway access drove this growth. The Tobu Railway reached the area in August 1899 with a 40 km steam line from Kitasenju to Kuki, stopping at Koshigaya (now Koshigaya-Kita) among eight stations.[10](https://adeac.jp/koshigaya-city-digital-archives/texthtml/d000110/mp001980-100020/ht000480) The present Koshigaya Station opened in 1920, and through service with the [Tokyo subway](https://www.edgepedia.org/tokyo-subway)'s Hibiya Line began in 1962, which the city's history credits with accelerating its urbanization.[10](https://adeac.jp/koshigaya-city-digital-archives/texthtml/d000110/mp001980-100020/ht000480) The JR Musashino Line opened across the city in April 1973, adding Minami-Koshigaya Station, and Shin-Koshigaya Station followed in July 1974 as a transfer point.[10](https://adeac.jp/koshigaya-city-digital-archives/texthtml/d000110/mp001980-100020/ht000480) Today the Musashino Line runs east to west through Minami-Koshigaya and Koshigaya-Laketown, and the Tobu Isesaki Line runs north to south through six stations from Sengen-dai to Gamo; National Routes 4 and 463 also cross the city.[2](https://www.koshigaya.city/p/about.html)
## Koshigaya Lake Town and flood control
The city's largest recent development turned its flood problem into a planning asset. The area around the Nakagawa and Motoarakawa rivers had suffered repeated river flooding and long remained undeveloped despite good access to Tokyo.[11](https://documents1.worldbank.org/curated/en/915131601460271575/pdf/Appendix-Case-Studies-in-Integrated-Urban-Flood-Risk-Management-in-Japan.pdf) Beginning in 1999, the Urban Renaissance Agency, working with the national and prefectural river administrators, carried out the Koshigaya Lake Town project, combining a large-scale flood-control reservoir with a residential environment on a site of roughly 230 hectares.[5](https://www.ur-net.go.jp/overseas/achievements/koshigaya.html) • [11](https://documents1.worldbank.org/curated/en/915131601460271575/pdf/Appendix-Case-Studies-in-Integrated-Urban-Flood-Risk-Management-in-Japan.pdf)
**Compact-city design.** The project was built so that all urban functions lie within a 15-minute walk of the new railway station at its center, reducing dependence on cars, and it used solar energy and other measures to lower carbon dioxide emissions.[5](https://www.ur-net.go.jp/overseas/achievements/koshigaya.html) It was the first project in Japan to develop a new urban area through a land readjustment project (pooling land to build infrastructure, sharing gains) combined with a river-regulating reservoir, and it received the LivCom Awards 2009 Gold Award for environmentally sustainable projects.[12](https://www.mlit.go.jp/common/001191684.pdf) • [5](https://www.ur-net.go.jp/overseas/achievements/koshigaya.html) The World Bank and other international bodies cite Lake Town as an example of integrating urban flood risk management with housing development.[11](https://documents1.worldbank.org/curated/en/915131601460271575/pdf/Appendix-Case-Studies-in-Integrated-Urban-Flood-Risk-Management-in-Japan.pdf) • [13](https://www.worldbank.org/en/programs/tokyo-development-learning-center/tdd/tdd_on_urban_flood_management)
## Population and administration
The city's population stood at 341,059 in 166,413 households as of 1 October 2026, according to the city's own figures.[3](https://www.city.koshigaya.saitama.jp/) The prefecture's estimate for 1 October 2025 was 338,134, and a prefectural economic-promotion profile describes Koshigaya as ranking fifth among the prefecture's 63 municipalities, while the city's own page gives fourth place as of 1 January 2024; the two figures reflect different dates and sources.[14](https://www.pref.saitama.lg.jp/b0104/sityougaiyou/index.html) • [1](https://www.city.koshigaya.saitama.jp/citypromotion/oshiete/gaiyo/) The city's future vision, stated in its comprehensive plan, is a "safe, secure, and coexisting city where everyone plays an active role, blessed with water, greenery, and sun," and it continues to develop as a bedtown near Tokyo.[1](https://www.city.koshigaya.saitama.jp/citypromotion/oshiete/gaiyo/)
**Symbols.** The city emblem, adopted on 10 January 1955 after a public solicitation, has ten outer rings representing the merged 2 towns and 8 villages, four katakana "ko" characters forming the character for "koshi," and a stylized "tani" (valley) at the center.[2](https://www.koshigaya.city/p/about.html) A separate symbol mark, chosen by citizen vote from a national solicitation for the city's 40th anniversary on 3 November 1998, depicts "Suigo Koshigaya" and a parent and child shirakobato (azure-winged magpie) in flight.[2](https://www.koshigaya.city/p/about.html) The city tree is the zelkova (keyaki), designated in 1978.[2](https://www.koshigaya.city/p/about.html)
## References
1. [市の概要, Koshigaya City official website](https://www.city.koshigaya.saitama.jp/citypromotion/oshiete/gaiyo/)
2. [越谷市について, Koshigaya City portal site](https://www.koshigaya.city/p/about.html)
3. [越谷市公式ホームページ](https://www.city.koshigaya.saitama.jp/)
4. [越谷の沿革概要, Koshigaya City Digital Archives](https://adeac.jp/koshigaya-city-digital-archives/texthtml/d000060/mp001930-100020/ht000040)
5. [Case 03: Koshigaya Lake Town, Urban Renaissance Agency](https://www.ur-net.go.jp/overseas/achievements/koshigaya.html)
6. [越谷市, Saitama Resona Foundation for Industry and Economy](https://www.sarfic.or.jp/?interview=interview-1397)
7. [越谷市洪水ハザードマップ, Koshigaya City official website](https://www.city.koshigaya.saitama.jp/anzen_anshin/bosai/kasenchisui/kkhm.html)
8. [越谷市内水ハザードマップ, Koshigaya City official website](https://www.city.koshigaya.saitama.jp/anzen_anshin/bosai/kasenchisui/naisuihazardmap.html)
9. [越谷市自治基本条例（前文）, Koshigaya City](https://www.city.koshigaya.saitama.jp/kurashi_shisei/shisei/shingikai/sougou/jichikihonjoreishingi/jichi_tousin_090330_files_tousin_zentaiban_090330.pdf)
10. [鉄道と越谷, Koshigaya City Digital Archives](https://adeac.jp/koshigaya-city-digital-archives/texthtml/d000110/mp001980-100020/ht000480)
11. [Case Studies in Integrated Urban Flood Risk Management in Japan, World Bank](https://documents1.worldbank.org/curated/en/915131601460271575/pdf/Appendix-Case-Studies-in-Integrated-Urban-Flood-Risk-Management-in-Japan.pdf)
12. [Development of New Towns in Suburban Areas, MLIT](https://www.mlit.go.jp/common/001191684.pdf)
13. [Strengthening Disaster and Climate Resilience in Cities, World Bank Tokyo Development Learning Center](https://www.worldbank.org/en/programs/tokyo-development-learning-center/tdd/tdd_on_urban_flood_management)
14. [管内情報, Saitama Prefecture](https://www.pref.saitama.lg.jp/b0104/sityougaiyou/index.html)
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*Topic: Encyclopedia › Places and geography › Settlements and neighborhoods › Cities and towns › Cities, towns, and villages of East Asia › Cities, towns, and wards of Japan › Cities of the Kantō region*
*Initially written Oct 21, 2026*
*Copyright 2026 EdgeChat AI, a subsidiary of Biostate AI.*
License: Edgepedia Community License 1.0, https://www.edgepedia.org/edgepedia/license