The Province of Frosinone is a province in the region Lazio in Italy. It is made out of 91 comuni and it is a very beautiful province thanks to the many green countryside areas. Through the province of Frosinone runs the Cosa River, an important part of Frosinone's history, many necropolis were found alongside this river. Other main sites of the province include the Caverns of Pastena, the Caves of Collepardo, mountains and hills, but medieval buildings as well, such as churches and cathedrals, historic monuments, palaces and more.