Châtillon-sur-Chalaronne (French pronunciation: [ʃatijɔ̃ syʁ ʃalaʁɔn], literally Châtillon on Chalaronne) is a commune in the Ain department in eastern France.

The town takes its name from a castle built around 1000 AD.

The Chalaronne flows northwest through the commune and crosses the town.

It flows into the Saône from the left, between Saint-Didier-sur-Chalaronne and Thoissey.

This Ain geographical article is a stub.