It is situated on the top of the Sintra Mountains, where it has a panoramic view of the municipality of Sintra, and on a clear day Mafra and Ericeira. It is accessible from Santa Maria e São Miguel by a protected gate and turnstile, or across a road accessway to the Palace of Pena.The castle is located in the limits of the Sintra-Cascais Nature Park, in the north flank of the Sintra Mountains, where the slopes are at most 40% gradients, with accented or moderate variation. The Serra da Sintra, known locally, consists of an eruptive massif with an abundance of granite, sienitos, gabros and dioritos rock formations, with soils consisting of litólicos, húmicos, câmbicos, normais, de granito (Mng).
The climate is characterized by low temperatures and elevated precipatation, due to its proximity to the sea, its relief and dense vegetation. The local vegetation is dense and diverse, with a large percentage exotics introduced during the 16th century by D. João de Castro, and in the 19th century by Ferdinand II and Francis Cook. Further, the fauna is characterized by a similar diversity, and was integrated into the royal estates and hunting grounds, including the Tapada dos Bichos, Tapada do Inhaca, Tapada do Borges, Pinhal do Prior and Tapada do Forjaz, Pinhal do Sereno, Pinhal do Tomado and Pinhal do Vale dos Anjos.
Within the proximity of the castle are many other sites, including the Garden of Pena (Portuguese: Parque da Pena), the Estate of Penha Verde (Portuguese: Quinta da Penha Verde), the Estate of Regaleira (Portuguese: Quinta da Regaleira), the Estate of Relógio (Portuguese: Quinta do Relógio) and the Park of Monserrate (Portuguese: Parque de Monserrate), among others. The Moorish Castle and other properties in the region act as a principal focus of tourism, the principal activity in this region.
http://en.wikipedia.org/wiki/Castle_of_the_Moors_%28Sintra%29