It is located in northeastern Honshu, rising in the Japanese Alps and flowing generally northeast through Nagano and Niigata Prefectures before emptying into the Sea of Japan.

Originally, the Shinano River would have drained straight into an estuary-like Fukushima lagoon[6]: 41  before making its way into the Sea of Japan after flowing down from the Japanese Alps.

[7][8] Estimates presented in 1993 place the amount of loose sediment in the river system at 400–500 cubic metres per kilometre (840–1,050 cu yd/mi).

It has uncovered some of the earliest examples of Flame-style pottery (kaen doki), dating from the Middle Jōmon period (3500–2500 BCE), found at Sanka excavation site in Nagaoka, Niigata, near the confluence of the Sai and Shinano Rivers.

[6]: 37–38  There is limited evidence which has caused some historians (such as Shishi Tokamachi) to suggest that the Shinano system was not widely used for boat travel until the eighteenth century.

[6]: 32, 50 The confluence of the Chikuma and Sai rivers, called the Kawanakajima Plain, was the location a series of battles in the sixteenth century as part of the Sengoku period.

[17] The Shinano River incident involved 1,200 workers, approximately 600 of whom were Korean, who were subjected to regular mistreatment by their Japanese foremen.

News articles at the time alleged that up to 100 Koreans were killed during construction and that local farmers had reported seeing bodies floating down river.

After its confluence with Uono River, the Shinano is crossed by Koshiji Bridge and the Shinetsu train line before emerging onto Echigo Plains of the Niigata Prefecture at Sanjō.

The river turns northeast and flows through Niigata City for approximately 6 kilometres (3.7 mi) before finally emptying into the Sea of Japan.

The current Bandai Bridge, built in 1929 and designated as a nationally important cultural property, is only 306.9 metres (1,007 ft) long.

[7][24] Due to seasonal high rainfall in the Shinano's watershed the fertile farmlands on the Niigata plain were subjected to flooding every three to four years which destroyed crops, particularly rice, and villages.

[25] Attempts from local residents to secure funding to build a diversion channel began in the mid-early eighteenth century, during the Kyōhō era.

Likewise, drier land has also allowed for the construction of infrastructure such as expressways and the Shinkansen express-train network, to support a greater population in the area.

As a result, another channel, which was originally planned in the Edo period (1700s–1800s), was built on the western outskirts of Niigata City to further mitigate the risk of flooding and to help prevent saltwater intrusion into the Shinano estuary.

[1] The Chikuma River originates in the Japanese Alps at altitudes of above 2,000 metres (6,600 ft) and has a basin in its own right of 7,163 square kilometres (2,766 sq mi).

By the time the river flows onto the Echigo Plain, however, much more land is devoted to agriculture and there is huge potential for irrigation, especially due to influence of the Ohkouz Channel and weir.

The low precipitation is primarily due to its encirclement by the three ranges which make up the Japanese Alps and by the Jōshin'etsu-kōgen National Park.

The heavy snow melt is responsible for much of flooding to affect the Echigo, but also allows for the hydroelectricity generation and regular irrigation.

The construction of weirs and dams to support agriculture and industry as well as the introduction of invasive species and pollution have been the main causes of ecosystem degradation.

[40][41] The construction of large dams, especially in the mid and upper reaches of the system have significantly affected the ability of fish to migrate up and down the river, and into the Sea of Japan.

[47] In addition to these natural attractions, human involvement in the area is also responsible for making tourism a large part of the regional economy.