The park is named for the principal geomorphological unit that covers the entire area, designated the Arrábida cordillera or massif, consisting of three subareas:
an area of small elevations in the area around Sesimbra, associated with the Serra do Risco and Serra da Arrábida, consisting of hilltops between Outão and Setúbal;
a zone between the Serra de São Luís and the Serra dos Gaiteiros; and
an area formed by the Serras do Louro and Serra de São Francisco.

This group is oriented east-northeast to west-southwest (alpine orientation) covering an area of about 35 kilometres (22 mi) long and 6 kilometres (3.7 mi) wide, approximately 501 metres (1,644 ft) associated with the Formosinho anticline.
Arrábida was formed from four successive phases of rifting that resulted in the fragmentation of Laurasia and the formation of the north Atlantic.
This area is unique in the Atlantic for demonstrating the western propagation of the Tethys sea and the formation of the Mediterranean, caused by the collision of the African plate and the Eurasian plate, during the Late Cretaceous.
Geologically, the mountainous region was created during the Jurassic and Miocene epochs, while the plains formed during the Pliocene and Quaternary periods.
Ribeiro (1935) indicates that the massif began to be formed with successive movements during the Tertiary era.

It is formed by three lines of dislocation, oriented more or less to the east, which succeeded a retreat from the southeast to northeast.
This first area is represented by part of northern flanks of various anticlines; the second is formed by anticlines a little more inclined to the south, a third by folds and horizontal thrusts in the extreme east.

The same author (1937) indicated that the peninsula of Setúbal was, during the Mesozoic, covered by shallow seas.
During a great part of the Jurassic, Arrábida was a marine ecosystem covered by ocean, resulting in the formation of Dolomite limestones, today being constituted by white limestone.
From the Jurassic there was a movement of submersion, that formed "alternating layers of limestone, sandstone and breccia, with a clear angular unconformity on the previous limestone that ministered part of the material".
The sedimentary breccia is a valuable ornamental stone, more commonly known as Arrábida Marble.

Among the notable geomorphologic points-of-interest are the Morro de Palmela, at 232 metres (761 ft), the Montes de Azeitão, that include the Serra do Louro, at 254 metres (833 ft)) and the Serra de São Francisco 257 metres (843 ft)).
Parallel to the Serra do Louro, and more to the south, is the Serra de Gaiteiros, at 226 metres (741 ft), to the southwest the Serra de São Luís, at 395 metres (1,296 ft) and to the southeast the Serro do Viso at 168 metres (551 ft).
Along the coast is the actually Serra da Arrábida, with its highest point at 499 metres (1,637 ft) (Formosinho).
Over the sea and abrupt cliffs are the Serra do Risco and Píncaro, the highest point along the Portuguese coast in this area, at approximately 380 metres (1,250 ft).
These mountains are constituted from limestone cliffs, with frequent rocky outcroppings forming of scenic cliffs.
Arrábida is dotted by karst cavities, that include the Gruta do Frade, known for singular, rarity, diversity and scenic beauty.
From a paleontological perspective there are fossil deposits that include fragments of dinosaurs (normally sauropods), relevant to scientific investigation, commonly associated with the Cabo Espichel.

There are also valleys of important interest, including south of the Serra de São Francisco until Aldeia Grande, the Vale de Barris and the Vale de Alcube.
Between the Serra da Arrábida and the western Montes de Azeitão, is the Vale de Picheleiros, that continue from the Vale da Ribeira da Ajuda to Várzea da Comenda.
There is also the Vale do Solitário, between the coastal flanks of Arrábida and the Cabeços do Jaspe and Guincho, and the Vale da Vitória, in the subplateau of the Serra do Risco.
The coast from Sesimbra and Alpertuche is more varied and elevated then the Cabo Espiche
The park is named for the principal geomorphological unit that covers the entire area, designated the Arrábida cordillera or massif, consisting of three subareas:
an area of small elevations in the area around Sesimbra, associated with the Serra do Risco and Serra da Arrábida, consisting of hilltops between Outão and Setúbal;
a zone between the Serra de São Luís and the Serra dos Gaiteiros; and
an area formed by the Serras do Louro and Serra de São Francisco.
This group is oriented east-northeast to west-southwest (alpine orientation) covering an area of about 35 kilometres (22 mi) long and 6 kilometres (3.7 mi) wide, approximately 501 metres (1,644 ft) associated with the Formosinho anticline. Arrábida was formed from four successive phases of rifting that resulted in the fragmentation of Laurasia and the formation of the north Atlantic. This area is unique in the Atlantic for demonstrating the western propagation of the Tethys sea and the formation of the Mediterranean, caused by the collision of the African plate and the Eurasian plate, during the Late Cretaceous. Geologically, the mountainous region was created during the Jurassic and Miocene epochs, while the plains formed during the Pliocene and Quaternary periods. Ribeiro (1935) indicates that the massif began to be formed with successive movements during the Tertiary era.
It is formed by three lines of dislocation, oriented more or less to the east, which succeeded a retreat from the southeast to northeast. This first area is represented by part of northern flanks of various anticlines; the second is formed by anticlines a little more inclined to the south, a third by folds and horizontal thrusts in the extreme east.
The same author (1937) indicated that the peninsula of Setúbal was, during the Mesozoic, covered by shallow seas. During a great part of the Jurassic, Arrábida was a marine ecosystem covered by ocean, resulting in the formation of Dolomite limestones, today being constituted by white limestone. From the Jurassic there was a movement of submersion, that formed "alternating layers of limestone, sandstone and breccia, with a clear angular unconformity on the previous limestone that ministered part of the material". The sedimentary breccia is a valuable ornamental stone, more commonly known as Arrábida Marble.
Among the notable geomorphologic points-of-interest are the Morro de Palmela, at 232 metres (761 ft), the Montes de Azeitão, that include the Serra do Louro, at 254 metres (833 ft)) and the Serra de São Francisco 257 metres (843 ft)). Parallel to the Serra do Louro, and more to the south, is the Serra de Gaiteiros, at 226 metres (741 ft), to the southwest the Serra de São Luís, at 395 metres (1,296 ft) and to the southeast the Serro do Viso at 168 metres (551 ft). Along the coast is the actually Serra da Arrábida, with its highest point at 499 metres (1,637 ft) (Formosinho). Over the sea and abrupt cliffs are the Serra do Risco and Píncaro, the highest point along the Portuguese coast in this area, at approximately 380 metres (1,250 ft). These mountains are constituted from limestone cliffs, with frequent rocky outcroppings forming of scenic cliffs. Arrábida is dotted by karst cavities, that include the Gruta do Frade, known for singular, rarity, diversity and scenic beauty. From a paleontological perspective there are fossil deposits that include fragments of dinosaurs (normally sauropods), relevant to scientific investigation, commonly associated with the Cabo Espichel.
There are also valleys of important interest, including south of the Serra de São Francisco until Aldeia Grande, the Vale de Barris and the Vale de Alcube. Between the Serra da Arrábida and the western Montes de Azeitão, is the Vale de Picheleiros, that continue from the Vale da Ribeira da Ajuda to Várzea da Comenda. There is also the Vale do Solitário, between the coastal flanks of Arrábida and the Cabeços do Jaspe and Guincho, and the Vale da Vitória, in the subplateau of the Serra do Risco. The coast from Sesimbra and Alpertuche is more varied and elevated then the Cabo Espiche
Arrábida Natural Park