Comunidade Intermunicipal do Oeste is an administrative division of Portugal, located on the country's western central coast. The population in 2011 was 362,540, in an area of 2,220.16 square kilometres (857.21 sq mi). Caldas da Rainha serves as the seat of Oeste.

Caldas da Rainha is a medium-sized Portuguese city in the Oeste region, in the historical province of Estremadura, and in the district of Leiria. 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 (98.72 sq mi), with 30,343 residing in the city. Although the city itself lies about 10.5 kilometres (6.5 mi) 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.