County Cavan is a county in Ireland. It is in the province of Ulster and is part of the Northern and Western Region. It is named after the town of Cavan and is based on the historic Gaelic territory of East Breffny (Bréifne). Cavan County Council is the local authority for the county, which had a population of 81,704 at the 2022 census.

There are four provinces of Ireland: Connacht, Leinster, Munster and Ulster. The Irish word for this territorial division, cúige, meaning "fifth part", suggests that there were once five, and at times Meath has been considered to be the fifth province. In the medieval period, however, there were often more than five. The number of provinces and their delimitation fluctuated until 1610, when they were permanently set by the English administration of James I. The provinces of Ireland no longer serve administrative or political purposes but function as historical and cultural entities.