Carhaix is located in the eastern part of the department of Finistère, very close to the departments of Côtes-d'Armor and Morbihan.
In 1956, Carhaix absorbed the neighbouring municipality of Plouguer and the municipality of Carhaix-Plouguer was formed.
Carhaix is located very close to the region where the Breton culture survived the best and was revived by famous artists such as the sisters Maryvonne, Eugénie and Anastasie Goadec, specialized in the kan-ha-disk songs, from Treffrin, and the sonnar (piper) and instrument maker Per Guillou.