This region faces the Tyrrhenian sea with a littoral zone which is dominated by the Gulf of Naples. This area consists mostly of wide plains, though these are intermixed with mountainous projections of volcanic (Campi Flegrei and Somma-Vesuvio) and sedimentary origin (Massico and Lattari) There is also the somewhat uneven inner zone which is interrupted by an area of low elevation.
The area of greatest importance in the littoral section is the very fertile lowland countryside intersected in the north by the Volturno and in the south by the Sarno. The two other lowland plains, the Garigliano to the north and the Sele to the south do not extend so far. Various islands present themselves along the length of the coast, some volcanic (Ischia and Procida) and others such as Capri are of limestone.
The Apennine chain encloses the middle highlands of this section of the peninsula with a series of mountainous peaks succeeding each other from north to south and flanked to the east by a less rugged zone of flat plains broken up by valleys (e.g. Benevento). This region has very diverse climatic conditions. While the littoral zone enjoys a very mild climate and an annual average temperature of 16 C (61 F), the Apennine regions have a much lower average together with a higher rainfall in the coastal area of Campi Flegrei and in the hollow of Benevento.
The vegetation – in accordance to the geographical and climatic conditions - is very varied: there are the Mediterranean thickets of the littoral zone which stretch up as far as a height of 400 metres, oak and chestnut woodland (up to 1000 metres ) and beech woodland (up to 1600 metres), after which the mountain pastures take over.
The population of this region is unevenly distributed: only a small percentage (about 15%) live in the country, the remainder being centrally distributed near the Gulf of Naples and the Sorrento peninsula, on the fertile lower slopes of Vesuvius and on the heights surrounding the lower plains.