Sarno is geographically part of the Agro Nocerian-Sarnian area; it develops in the foothills of the Saro and on the banks of the Sarno river, from which the name of the city is taken. The waters of its river have made possibile for many civilizations over the millennia to settle in the homonymous valley. 

Mount Somma is a mountainous relief partially surrounding Vesuvius, characterized by seven peaks called Cognoli.