County Cavan (Irish: Contae an Chabháin) is a county in Ireland. It is part of the Border Region and is also located in the province of Ulster. It is named after the town of Cavan. Cavan County Council is the local authority for the county. The population of the county is 72,874 according to the 2011 census.

Cavan borders six counties; Leitrim to the west, Fermanagh and Monaghan to the north, Meath to the south-east, Longford to the south-west and Westmeath to the south. Cavan shares a 70 km (43 mi) border with County Fermanagh in Northern Ireland. Cavan is the 19th largest of the 32 counties in area and the 25th largest by population. It is also the sixth largest of Ulster's nine counties in size and the seventh largest by population.

There are eight historic baronies in the county. While baronies continue to be officially defined units, they are no longer used for many administrative purposes. Their official status is illustrated by Placenames Orders made since 2003, where official Irish names of baronies are listed under "Administrative units".

Cavan ( /ˈkævən/; Irish: an Cabhán, meaning "the hollow") 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. 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. King James I granted the town a charter in 1610. Later during the 17th century local administrative influence and power passed to the Maxwell family, descendants of Robert Maxwell, Bishop of Kilmore (1643-72), who later became titled Lords Farnham.