is a district located in Nagano Prefecture, Japan.
As of November 1, 2005, the district has an estimated population of 34,759 with a density of 22.48 persons per km<sup>2</sup>. The total area is 1,546.26 km<sup>2</sup>.
The district consists of three towns and three villages:
Historically, the district was once known as until May 1, 1968.