Zagarolo is a town and comune in the province of Rome, in the region of Lazio of central Italy. It has 17,803 inhabitants and a total area of 28 square kilometres (11 sq mi). It lies 34 kilometres (21 mi) south-east of Rome, and it borders the municipalities of Colonna, Gallicano nel Lazio, Monte Compatri, Palestrina, Rome, San Cesareo (former frazione of Zagarolo). The historical town center of Zagarolo lies on a very narrow tuff hill, 2 kilometres (1.2 mi) long and about 100 metres (330 ft) wide, at an elevation of 310 metres (1,020 ft), surrounded by green valleys. The south continuation of the important pilgrim route Via Francigena passes through the countryside of Zagarolo.