Diocese of Ferentium is a former bishopric (now titular see) with capital in town Ferentium near Viterbo (in Lazio, Central Italy), which absorbed it.
Diocese Ferentium was established around 400 AD.
In 1970, the old diocese was nominally restored as a Latin titular see.
It has had the following incumbents, of both the lowest (episcopal) and intermediate (archiepiscopal) ranks:
This article about a Roman Catholic titular see in Europe is a stub.