is a town located in Nagano Prefecture, Japan. , the town had an estimated population of 11,045 in 4892 households, and a population density of 23 persons per km<sup>2</sup>. The total area of the town is . Kiso Town is listed as one of The Most Beautiful Villages in Japan.
Kiso is located in mountainous southwest Nagano Prefecture, bordered by Gifu Prefecture to the west.
The town has a climate characterized by characterized by warm and humid summers, and cold winters with heavy snowfall (Köppen climate classification Dfb). The average annual temperature in Kiso is . The average annual rainfall is with July as the wettest month. The temperatures are highest on average in August, at around , and lowest in January, at around .
The area of present-day Kiso was part of ancient Shinano Province.
The modern town was created through a merger of the town of Kiso-Fukushima with the villages of Hiyoshi, Kaida and Mitake on November 1, 2005.
Per Japanese census data, the population of Kiso has quickly fallen over the past 60 years and is now less than half of what it was in 1940.
Kiso has four public elementary schools and three public middle schools operated by the town government, and one high school operated the Nagano Prefectural Board of Education. The prefectural also operates a special education school. The Solar-Terrestrial Environment Laboratory, Nagoya University is located in Kiso.
Kurokawa Elementary School opened in 1928 and closed in 1997; in 2022 it became a museum showcasing wooden toys.