The arrondissement of Châteaulin is an arrondissement of France in the Finistère department in the Brittany region.

[2] Its population is 81,081 (2021), and its area is 1,756.6 km2 (678.2 sq mi).

[3] The communes of the arrondissement of Châteaulin, and their INSEE codes, are:[2] The arrondissement of Châteaulin was created in 1800.

[5] As a result of the reorganisation of the cantons of France which came into effect in 2015, the borders of the cantons are no longer related to the borders of the arrondissements.

The cantons of the arrondissement of Châteaulin were, as of January 2015:[6]