Situated at the south-eastern tip of the Italian peninsula, Apulia covers over 19,000 square kilometers (7,336 sq mi) in succession of broad plains and low-lying hills. The central area of the region is occupied by the Murge, a vast karst plateau and Itria Valley. The only mountainous areas, the Gargano promontory and the Monti Dauni, do not exceed 1,150 m (3,800 ft) and are to be found in the north of Apulia, which is the least mountainous region in Italy.
Apulia is a very dry region. Its few rivers are torrential and are to be found on the in southern Murge, where is the Canale Reale, on Tarantine, where is the Geleso river, and on the Tavoliere delle Puglie a tableland at the foot of the Gargano promontory that is one of the largest and agriculturally most productive plains in Italy. Elsewhere, rainwater permeates the limestone bedrock to form underground watercourses that resurface near the coast. Groundwater is therefore abundant, and there are many caves and sinkholes. The caves at Castellana Grotte are particularly spectacular.