Sintra (ˈsɪntrə,_ˈsiːntrə, ˈsĩtɾɐ) is a town and municipality in the Greater Lisbon region of Portugal, located on the Portuguese Riviera. The population of the municipality in 2021 was 385,654, in an area of . Sintra is one of the most urbanized and densely populated municipalities of Portugal. A major tourist destination famed for its picturesqueness, the municipality has several historic palaces, castles, scenic beaches, parks and gardens.
The area includes the Sintra-Cascais Nature Park through which the Sintra Mountains run. The historic center of the Vila de Sintra is famous for its 19th-century Romanticist architecture, historic estates and villas, gardens, and royal palaces and castles, which resulted in the classification of the town as a UNESCO World Heritage Site. Sintra's landmarks include the medieval Castle of the Moors, the romanticist Pena National Palace and the Portuguese Renaissance Sintra National Palace.
Sintra is one of the wealthiest municipalities in both Portugal and the Iberian Peninsula as a whole. It is home to one of the largest foreign expat communities along the Portuguese Riviera and consistently ranks as one of the best places to live in Portugal.
The ECB Forum on Central Banking, an annual event organised by the European Central Bank, is held in Sintra.
The earliest remnants of human occupation were discovered in Penha Verde: these vestiges testify to an occupation dating to the early Paleolithic. Comparable remnants were discovered in an open-air site in São Pedro de Canaferrim, alongside the chapel of the Castelo dos Mouros (Moorish Castle), dating back to the Neolithic, and include decorated ceramics and microlithic flint utensils from the 5th millennium BC.
Ceramic fragments found locally including many late Chalcolithic vases from the Sintra mountains suggest that between the fourth and third millennia B.C. the region (adjacent to the present village of Sintra) was occupied by a Neolithic/Chalcolithic settlement, with characteristics comparable to fortified settlements in Lisbon and Setúbal.