Lake Atsugishi has an oyster island (officially Benten Island) and a small Benten shrine. Although the date of the shrine's founding is not certain, it is recorded in the Kansei 3 (1791) record, and it is also recorded that a festival was held there in the Bunsei 3 (1820) record.
In addition, this island used to be large in area and even had a recreation center and a ryotei (Japanese-style restaurant), but has now become smaller due to land subsidence.