Acquaviva (literally "living water") is one of the 9 communes or "castelli" of San Marino.
It has 2,145 inhabitants (May 2018) in an area of 4.86 km². It borders the San Marino municipalities Borgo Maggiore and San Marino and the Italian municipalities San Leo and Verucchio.
In its territory there are two significant sites for San Marino. The first, the rock of Baldasserona, is considered the location of the Titan where he stopped for the first time Saint Marino. In the rock which is in fact a large fissure, is considered the first refuge of the founder of San Marino. In fact, for San Marino, it is precisely at this point that began their history. Another place that has marked the history of San Marino is Mount Cerreto. At the foot of the hill, was the information with which the Saint baptized the first Christians of the Titano community, and hence the name of "Acquaviva". Finally, historical documents attest that "the Cerreto Castello di Monte", identified with Acquaviva, in 885 was issued the "Placito Feretrano", the oldest document of the Republic of San Marino.