Lake Kawaguchi is one of the five lakes surrounding Mt. Fuji. These lakes were formed as a result of barrage formation by volcanic debris and solidified magma spewed out of Mt. Fuji and the off-spring volcanic outlets nearby. The lake is the oldest of the five and it is at least 50-60 thousand years old. There are scores of underwater springs at the lake bottom. There is no discernible surface flow into or out of the lake. Major flows of water appear to take place underground.

In 1912 a sluiceway was constructed to discharge a maximum flow of 7.79 m³ sec^-1 (named Usobuki River). Artificial regulation of flow has been made possible by flow augmentation from Lake Sai, one of the remaining four lakes, for supplementing water for power generation. The number of visitors to the five-lake area exceeds ten million annually. Lake Kawaguchi, directly linked to Tokyo Metropolitan urban districts through a major artery highway and closest to the terminal of the Fuji Subaru scenic route, is a centre of tourist attraction in this area.

The transparency of the lake was 4-7 m some 60 years ago, but the 1972 measurement indicated only 3-4 m. A regional sewerage project was initiated in 1974 and the provision of service to portion of the area has begun in 1986 (Q).