Alcobaça is a Portuguese city and municipality in the Oeste region, in the historical province of Estremadura, and in the Leiria District. The city grew along the valleys of the rivers Alcoa and Baça, from which it derives its name. The municipality population in 2011 was 56,693, in an area of 408.14 square kilometres (157.58 sq mi). The city proper has a population of 15,800 inhabitants.

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.