Sintra municipality and town is in the Grande Lisboa sub region (Lisbon Region) of Portugal, considered part of the Portuguese Riviera. The municipality contains two cities: Queluz and Agualva-Cacém. The population in 2011 was 377,835, in an area of 319.23 square kilometres (123.26 sq mi)

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 centre and suburbs of the capital Lisbon.

In addition to the Sintra Mountains and Sintra-Cascais Nature Park, the parishes of the town of Sintra are dotted with royal retreats, estates, castles and other buildings, including the mediaeval Castelo dos Mouros, the Pena National Palace and the Sintra National Palace.

From a policing point of view the majority of the municipality is under the command of the GNR, under the command structure of the GNR Lisbon Territorial Command. The palace areas and the town itself as well as the urban area to the south east are under the command of the PSP Lisbon Metropolitan police command.