Caldas da Rainha is a medium-sized city in the district of Leiria of Portugal. The city serves as the seat of the larger municipality of the same name and of the Comunidade Intermunicipal do Oeste. At the 2011 census, the municipality had a population of 51,729 in an area of 255.69 square kilometres, with 30,343 residing in the city. Although the city itself lies about 10.5 kilometres inland, three of the municipality's civil parishes lie on the Atlantic Ocean. Caldas da Rainha is best known for its sulphurous hot springs and ceramic pottery.
The settlement was founded in the 15th century by Queen Leonor, who established a hospital and a church at the site of some therapeutic hot springs. The Hospital Termal Rainha D. Leonor is the oldest purpose-built institution of its kind in the world, with five centuries of history. The city's name, often shortened to simply "Caldas", can be translated as "Queen's Hot Springs", "Queen's Spa", or "Queen's Baths".
Caldas da Rainha is a UNESCO Creative City. It is home to many cultural institutions. The city's nine museums cover art, history, and cycling.