The municipality has a population of 3,554 (31 December 2024)[6] and covers an area of 495.41 square kilometres (191.28 sq mi) of which 39.01 km2 (15.06 sq mi), or almost 8%, is water.

[1] The population density is 7.79 inhabitants per square kilometre (20.2/sq mi).

Neighbouring municipalities are Jyväskylä, Jämsä, Keuruu, Multia and Uurainen.

Karikkoselkä is a lake in Petäjävesi, which is formed by a meteorite.

[8] The Karikkoselkä impact crater is located southeast of the municipal centre.