Placenames or geographical names whose official, legal Irish versions are specified in various Placenames Orders in accordance with the Official Languages Act 2003. Certain placenames in Northern Ireland are also included in this category, such as counties, cities, towns and various other population centres.
Placenames or geographical names for which provisional Irish forms have been recommended by the Placenames Branch on the basis of research but which are not specified in Placenames Orders in accordance with the Official Languages Act 2003.
Historical forms of placenames or obsolete placenames.
Local forms of placenames which are variants of official names. In certain cases there is a change to another name or to an Irish-language form of a name.