Puy-de-Dôme is a department in the Auvergne-Rhône-Alpes region in the centre of France. In 2021, it had a population of 662,285. Its prefectu…Puy-de-Dôme is a department in the Auvergne-Rhône-Alpes region in the centre of France. In 2021, it had a population of 662,285. Its prefecture is Clermont-Ferrand and subprefectures are Ambert, Issoire, Riom, and Thiers.