The first time it was mentioned as a town was in 1229, when it was an important trading post on the road between Ljubljana and Celje.

The town was among the most influential centers of power for the Bavarian counts of Andechs in the region of Carniola at the time.

The only remnant of the Bavarian nobility are the two ruined castles which are both strategically built on high ground near the town center.

Kamnik is the site of a mass grave from the period immediately after the Second World War.

The Cuzak Meadow Mass Grave (Slovene: Grobišče Cuzakov travnik) is located in the southeast part of the town, in a grassy area encircled by a road on the premises of the Svit factory.