
This is a list of the counties of Ireland ordered by area. Counties in the Republic of Ireland are shown in normal type, while those in Northern Ireland are listed in italic type.

The counties of Ireland are historic administrative divisions of the island, now used in various contexts. They began as Norman structures, and as the powers exercised by the Cambro-Norman barons and the Old English nobility waned over time, new offices of political control came to be established at a county level.

This is a list of counties of Ireland ordered by population. Counties in the Republic of Ireland are shown in normal type, while those in Northern Ireland are listed in italic type. Non-traditional administrative counties are indicated by a cream-coloured background.

This is a list of the baronies of Ireland. Baronies were subdivisions of counties, mainly cadastral but with some administrative functions prior to the Local Government (Ireland) Act 1898.

The following types of local government areas existed in the island of Ireland at this period having been brought into existence by the Local Government (Ireland) Act 1898:Administrative counties County boroughs Urban districts Rural districts Municipal boroughs, which were governed by the Municipal Corporations (Ireland) Act 1840, and Town commissioners which were governed by the Towns Improvement (Ireland) Act 1854. The latter had limited powers, forming part of a rural district for most purposes.

This is a list of Irish counties by their highest point. These are most commonly known as county high points but are also sometimes referred to as county tops and county peaks. There are 32 counties in Ireland, but in the case of 10 counties, marked with (‡), the highest point is shared between two counties, so there are only 27 distinct Irish county high points. This list is generated from the Irish MountainViews Online Database, and the overall ranking of an Irish County High Point against all other peaks in Ireland, is based on the Vandeleur-Lynam definition where a peak must have a minimum topographic prominence of 15 metres (49 ft) to be on the list of peaks in Ireland. The four Irish provincial tops, more also referred to as province high points, are also listed. The listings of Irish county high points under the definitions of Irish mountains, are also provided.

This article lists all poor law unions in Ireland.

This is a list of seaports around the coast of the island of Ireland.