Kissingen was first mentioned as "oppidum" (town) in 1279. The town developed to a spa in the 1500s and recorded its first official spa guest in 1520. The rise of Bad Kissingen to a world famous and respected spa began with the rediscovery of the Rakoczy spring in 1737 and it grew to be a fashionable resort in the 19thC.
In 2021, the town became part of the transnational UNESCO World Heritage Site under the name "Great Spa Towns of Europe". The Great Spa Towns of Europe are a group of eleven spa towns from seven countries.They represent the development of European spa tradition from its roots in the antiquity to the peak in the 19th and early 20thC.