[1] Per Japanese census data,[2] the population of Tsuno peaked around the year 1950 and has declined by roughly two-thirds in the decades since.

During the Edo period, the area was part of the holdings of Tosa Domain ruled by the Yamauchi clan from their seat at Kōchi Castle.

The villages of Kamihayama (上半山村), Shimohayama (下半山村) and Higashitsuno (東津野村) ere established with the creation of the modern municipalities system on October 1, 1889.

Tsuno has a mayor-council form of government with a directly elected mayor and a unicameral village council of ten members.

In terms of national politics, the town is part of Kōchi 2nd district of the lower house of the Diet of Japan.