Cavan is the county town of County Cavan in Ireland. The town lies in the north central part of the island of Ireland, near the border with Northern Ireland. The town is on the main road - the N3 road - linking Dublin (to the south) with Enniskillen, Ballyshannon and Donegal Town (to the north).
The O'Reilly clan (still a very common surname in the area) established a castle in the town in the late 13th century. A Franciscan monastery was also established at around the same time. In the 15th century the local ruler, Bearded Owen O'Reilly set up a market which attracted merchants from Dublin and Drogheda. King James I granted the town a charter in 1610. Later during the seventeenth century local administrative influence and power transended to the Maxwell family, decsendants of the Bishop of Kilmore from the 1640's, who later became titled Lords Farnham. Development in Cavan during the early 19th century saw the building of a new wide street that still bears the name Farnham Street. Away from the markets area of the town, Farnham Street was lined with comfortable town houses, public buildings (such as the courthouse which dates from 1825, and churches.
The term life of Reilly was credited to the O'Reilly clans due to their great wealth and power, having issued their own currency during the 17th century. From the mid 19th century, Cavan became an important rail junction for the Midland Great Western Railway (MGWR) and those of the Great Northern Railway (GNR). The Town Hall was built in 1909. In 1938, work began on the Roman Catholic Cathedral of Saints Patrick and Felim. Five kilometres (3 mi) west of Cavan Town is the Church of Ireland Kilmore Cathedral, which contains a Romanesque doorway dating from the 12th century reputed originally to have come from Trinity abbey, located a short distance away upon an island in Lough Oughter .