Suburbicarian Diocese of Velletri–Segni

The Suburbicarian Diocese of Velletri–Segni is one of the Latinsuburbicarian dioceses, Catholic dioceses in Italy close to Rome with a special status and a cardinal bishop, the bishop of Velletri–Segni. Historically, the see of Velletri was combined with the see of Ostia from 1060 to 1914.

The cathedral in the city of Velletri is dedicated to Saint Clement.

Segni was a small town, a former Roman colony, sited approximately halfway between Rome and Montecassino. In the 12th century, the diocese possessed only seven castelli, 37 churches, 3 chapels, and 3 cloisters.