Nagiso (南木曽町, Nagiso-machi) is a town located in Nagano Prefecture, Japan.

The total area of the town was 215.93 square kilometres (83.37 sq mi).

[3] The area of present-day Nagiso was part of ancient Shinano Province.

The villages of Yomikaki, Tsumagoi and Tadachi merged to form the town of Nagiso on May 1, 1968.

Per Japanese census data,[5] the population of Nagiso has remained declined rapidly over the past 60 years.