Sintra is a town and a municipality in the Grande Lisboa subregion (Lisbon Region) of Portugal. The municipality contains two cities: Queluz and Agualva-Cacém. The population in 2011 was 377,835, in an area of 319.23 km².
Sintra is known for its many 19th-century Romantic architectural monuments, which has resulted in its classification as a UNESCO World Heritage Site. Although its heritage in buildings and nature is the most visible face of the historic individuality of Sintra, a whole literary heritage has made the area a legendary reference in Portuguese culture. It has become a major tourist centre, visited by many day-trippers who travel from the urbanized suburbs and capital of Lisbon. In addition to the Sintra Mountains and Sintra-Cascais Nature Park, the parishes of the town of Sintra are dotted by royal retreats, estates, castles and other buildings, including the Castelo dos Mouros, the Pena National Palace and the Sintra National Palace.