It is located in the region of Pirkanmaa. The municipality has a population of 1,749 (31 December 2023) and covers an area of 390.50 square kilometres (150.77 sq mi) of which 33.39 km (12.89 sq mi) is water. The population density is 4.9 inhabitants per square kilometre (13/sq mi).

The municipality is unilingually Finnish.

Politics

Results of the 2011 Finnish parliamentary election in Kihniö:

• True Finns 53.2%
• Centre Party 15.5%
• Christian Democrats 14.4%
• National Coalition Party 6.5%
• Social Democratic Party 5.9%
• Communist Party of Finland 2.3%
• Green League 1.1%
• Left Alliance 0.5%
• Pirate Party 0.5%

Results of the 2021 Finnish municipal elections, resulted in the True Finns being the largest group on the Kihniö council, in Kihniö.