Tsunan has a Humid subtropical climate with continental influences (Köppen Cfa/Dfa) characterized by hot, wet summers and cold winters with heavy snowfall.

[2] Per Japanese census data,[4] the population of Tsunan has declined steadily over the past 70 years and is now considerably less than it was a century ago.

The area of present-day Tsunan was part of ancient Echigo Province and was tenryō territory under the direct control of the Tokugawa shogunate in the Edo period.

Tsunan has a mayor-council form of government with a directly elected mayor and a unicameral city council of 14 members.

In terms of national politics, the town is part of Niigata 6th district of the lower house of the Diet of Japan.