The is a major

river A river is a natural stream of fresh water that flows on land or inside Subterranean river, caves towards another body of water at a lower elevation, such as an ocean, lake, or another river. A river may run dry before reaching the end of ...

in the northern

Kantō region The is a geography, geographical region of Honshu, the largest island of Japan. In a common definition, the region includes the Greater Tokyo Area and encompasses seven prefectures of Japan, prefectures: Chiba Prefecture, Chiba, Gunma Prefe ...

Japan Japan is an island country in East Asia. Located in the Pacific Ocean off the northeast coast of the Asia, Asian mainland, it is bordered on the west by the Sea of Japan and extends from the Sea of Okhotsk in the north to the East China Sea ...

. It is in length and has a basin area of . Located entirely within

Gunma Prefecture is a landlocked Prefectures of Japan, prefecture of Japan located in the Kantō region of Honshu. Gunma Prefecture has a population of 1,937,626 (1 October 2019) and has a geographic area of . Gunma Prefecture borders Niigata Prefecture and Fuk ...

, it is one of the prefecture's major rivers. It is also a major tributary of the

Tone River The is a river in the Kantō region of Japan. It is in length (the second longest in Japan after the Shinano River) and has a drainage area of (the largest in Japan). It is nicknamed Bandō Tarō (); ''Bandō'' is an obsolete alias of the ...

. The river is an important source of

hydroelectric power Hydroelectricity, or hydroelectric power, is Electricity generation, electricity generated from hydropower (water power). Hydropower supplies 15% of the world's electricity, almost 4,210 TWh in 2023, which is more than all other Renewable energ ...

, and 17 power plants are located on its banks.

Geography

The source of the Agatsuma River is Torii Pass ( in altitude), on the border of

Gunma is a landlocked prefecture of Japan located in the Kantō region of Honshu. Gunma Prefecture has a population of 1,937,626 (1 October 2019) and has a geographic area of . Gunma Prefecture borders Niigata Prefecture and Fukushima Prefecture to t ...

and

Nagano Prefecture is a Landlocked country, landlocked Prefectures of Japan, prefecture of Japan located in the Chūbu region of Honshu. Nagano Prefecture has a population of 2,007,682 () and has a geographic area of . Nagano Prefecture borders Niigata Prefecture ...

s. It gathers tributaries from

Mount Asama is an active complex volcano in central Honshū, the main island of Japan. The volcano is the most active on Honshū. The Japan Meteorological Agency classifies Mount Asama as rank A. It stands above sea level on the border of Gunma prefecture ...

and

Mount Kusatsu-Shirane is a active volcano, stratovolcano in Kusatsu, Gunma, Japan. It is called Kusatsu Shirane to differentiate it from the Mount Nikkō-Shirane on the other side of Gunma Prefecture. The summit of Kusatsu-Shirane volcano, located immediately north ...

and flows into the

Shibukawa is a city in Gunma Prefecture, Japan. , the city had an estimated population of 76,098 in 32,439 households, and a population density of . The total area of the city is . Shibukawa is the location of Ikaho Onsen, a popular hot spring resort. ...

city. The Agatsuma River drains most of northwest Gunma Prefecture.

Transportation

The

East Japan Railway Company The is a major passenger railway company in Japan and the largest of the seven Japan Railways Group companies. The company name is officially abbreviated as JR-EAST or JR East in English, and as in Japanese. The company's headquarters are in ...

Agatsuma Line The is a local rail line in Gunma, Japan, and is part of the East Japan Railway Company (JR East) network. Approximately following the Agatsuma River, it is 55.6 km between and stations. Operations Although the official start of the line ...

(a single track line) runs along the river from

Shibukawa Station is a junction railway station in the city of Shibukawa, Gunma, Japan, operated by the East Japan Railway Company (JR East). Lines Shibukawa Station is a station on the Jōetsu Line and is 21.1 kilometers from the starting point of the line at ...

in the east to the terminus at

Omae Station Smoked plum is the smoked fruit of Prunus mume, Asian plums, used in East Asian cuisine and medicine. It is called ''wūméi'' () in Mandarin Chinese, Mandarin, ''omae'' () in Korean, ''ubai'' (; ) in Japanese, and ''Ô mai '' in Vietnamese. Ove ...

in the west. Roughly divided into three sections, the river can be travelled by road using three National Highways: National Route 353 (in the east), National Route 145 (in the middle), and National Route 144 (in the west).

References

Rivers of Gunma Prefecture Rivers of Japan {{Japan-river-stub