Course around Alps Azumino Park

Lake Nakatsuna (中綱湖, Nakatsuna-ko) is a lake in Ōmachi Nagano Prefecture, Japan. It is one of the "Nishina Three Lakes" (Lake Aoki, Lake Nakatsuna and Lake Kizaki). Its sediments have been studied in an effort to better understand climate change in Japan, finding evidence of the Medieval Warm Period and Little Ice Age.

Ōmachi (大町市, Ōmachi-shi) is a city located in Nagano Prefecture, Japan. As of 1 March 2019, the city had an estimated population of 27,559 in 11861 households , and a population density of 49 persons per km². The total area of the city is 565.15 square kilometres (218.21 sq mi).