The history of Cransac features three key periods during which each of its three underground resources –spa waters, coal and thermal gases – has been used to good effect.
Until the 19th century, Cransac's mineral waters attracted many visitors to "take the cure". In 1850, for example, 4,000 came seeking relief for rheumatism, digestive disorders and skin conditions. But six years later, the arrival of the railway brought with it the mining companies, who were to operate coal mines in Cransac for over a century, causing the mineral water springs to be lost. In 1963 came another change of direction; following the closure of the mines, the first spa facility opened its doors. The effectiveness of the thermal gases and the considerable efforts made in redeveloping the town led to growing numbers of visitors seeking health benefits. This culminated in 2003 in the building of a new spa facility and the obtaining of France's Classified Tourist Resort label (Station Classée de Tourisme) in 2012. Cransac-Les-Thermes is now continuing to grow as a tourist, economic and cultural centre.