By the Roman occupation of the Iberian Peninsula, the architecture of Colares was carved by Latin inscriptions, such as one found near the mouth of the Maçãs River: SOLI ET LUNAE CESTIVIUS ACIDIVIS PERENNIS LEG.

After a period of Moorish occupation, armies loyal to Afonso Henriques conquered the region, as a sequence of their victory in Sintra, around 1147.

The region remained in the hands of the Crown until 1385, when it was donated by John I to the constable Nuno Álvares Pereira to compensate the mercenary for his support against Castile.

The parish of Nossa Senhora da Assunção was a bishopric rectory in the old comarca of Torres Vedras, and Colares was the seat of its own municipality, attributed to King Afonso III, in May 1255.

Its contains the settlements Almoçageme, Atalaia, Azenhas do Mar, Azóia, Colares, Eugaria, Gigarós, Mucifal, Penedo, Praia das Maçãs and Ulgueira.