Siilinjärvi is a municipality of Finland. The name, in Finnish, means "Hedgehog's Lake." Lakes are essential part of the geography of Siilinjärvi. There are 123 lakes, and the biggest of them are Kallavesi and Juurusvesi–Akonvesi. Water area is 106.85 km², which is 21% of the whole area of Siilinjärvi.