Counties of Ireland or between the three counties in the Dublin area. This system usually results in more populated counties having several constituencies: Dublin, including Dublin city, is subdivided into twelve constituencies, Cork into five. On the other hand, smaller counties such as Carlow and Kilkenny or Laois and Offaly may be paired to form constituencies. An extreme case is the splitting of Ireland's least populated county of Leitrim between the constituencies of Sligo–North Leitrim and Roscommon–South Leitrim. Each county or city is divided into Local electoral areas for the election of councillors. The boundaries of the areas and the number of councillors
County Offaly out across the county with the Bog of Allen extending into four other counties. The county consists of approximately 42,000 hectares of peatlands which is 21% of Offaly's total land area. Offaly contains approximately of forest and woodland area, which only amounts to 4.5% of the county's land area. This includes woodlands within the Slieve Blooms and the Lough Boora Parklands. Roughly 75% of Offaly's forested area is Conifer High Forest. The following are the historical baronies located in County Offaly: One of the earliest known settlements in County Offaly is at Boora bog which dates back to the Mesolithic