Comprises nearly all Cavan and part of Leitrim, Fermanagh, Meath, and Sligo counties. Suffragan of Armagh. First known bishop, Saint Fedlemid (or Felim; 6th century). His successors included Andrew MacBrady (1445-1455), Richard Brady (1580-1607), Hugh O'Reilly (1625-1628), Andrew Campbell (1753-1769 or 1770); residence at Cavan. Ruins of several abbeys may be seen in the diocese, including that of Creevelea, Drumlane, and the Abbey of the Holy Trinity on Trinity Island, a carved doorway of which may be seen in the Protestant cathedral of Kilmore.