|The Giants' Causeway, Northern Ireland. Photo used under Creative Commons from Locace|
**Edited to add: this is a very simplistic overview of the meanings behind some of the conflicting terms that are used about Northern Ireland. I'm not from Northern Ireland, so I'm far from the best person to comment on this. The following is intended as a very, very simple primer on terms that have the potential to be troublesome, but it is not a substitute for examining the many nuanced aspects of identity and history that have shaped the region**
The first confusing thing about Northern Ireland is the name. It is alternatively known as The North, the Six Counties, Ulster, the North of Ireland, the Province and very occasionally British-occupied Ireland. All of these names have connotations.
There are two main communities in Northern Ireland - unionists, who are quite happy to be ruled by the UK, and nationalists, who believe that Northern Ireland should be part of the Republic of Ireland. Within these very broad definitions, there is obviously a wide range of opinion, so what follows is not exhaustive. Unionists tend to use terms that emphasise Northern Ireland as a distinct entity - they are more likely to say Ulster, or the Province. Nationalists, on the other hand, tend to emphasise the geographical link with the Republic and are more likely to refer to the North, the Six Counties, or British-occupied Ireland (I haven't heard that one much myself, and it would mostly be used by people with more extreme views on the subject).
If you are writing about Northern Ireland, keep it simple and call it Northern Ireland. If you want to depict a unionist character, drop in an Ulster or two, and if you want to depict a nationalist character, have them call it 'the North', but the term 'Northern Ireland' is widely used.
In the Republic, we tend to call it The North. Which is technically incorrect because Co. Donegal, among others, is in what would be considered the extreme north of the country but is firmly and passionately part of the Republic (actually, the term Ulster is inaccurate too, because there are three counties in the Republic that are part of the region called Ulster but not part of the political entity that is Northern Ireland. See why I said it was complicated?).
The second city of Northern Ireland is rather simpler, but more divisive. You may know it as Derry or Londonderry. I know it as Derry, and some people know it from the song The Town I Loved So Well (if you're looking for a version of it to listen to, I like Luke Kelly's best).
During the Plantation of Ulster (a period of organised colonisation by England, when settlers from England and Scotland were sent to Northern Ireland to increase British control of the region), the city of Derry was substantially rebuilt and renamed Londonderry. It was popularly called Derry for several centuries until the outbreak of civil unrest ('The Troubles') in the 1960s, when the issue became politically charged and unionists began to use the official name Londonderry again. The city council, confusingly, is called Derry City Council, so when referring to local government issues, it is correct to say Derry. There has been debate for some years about whether or not to change the city's name to Derry officially, but the debate has been split completely along political lines. Unionists want one name and nationalists want the other, so the status quo has remained in place in the absence of a better suggestion. This happens a lot in Ireland, and probably everywhere else in the world too. . .
In the Republic, we say Derry, and you'd get a funny look for saying Londonderry - one of our government ministers called it Londonderry during a discussion in parliament earlier this year and it generated a lot of comment. It was as late as 2009 before we would accept passport applications that listed Place of Birth as Londonderry - prior to that, forms had to say Derry. Our road signs point to Derry. In Northern Ireland, both terms are used but it is highly politicised, so if writing, a character from the Republic of Ireland will say Derry, a Northern Irish unionist will say Londonderry and a Northern Irish nationalist will say Derry.
Wikipedia informs me that UK-based organisations have some creative solutions - the BBC will use Londonderry initially in any piece and then use both terms interchangably. The left-win Guardian newspaper suggests Derry and the right-wing Telegraph suggests Londonderry. The Northern Irish Civil Service are advised in correspondence to use whatever term their correspondant does. The last word, though, goes to Irish comedian Neil Delamere, who commented that the Irish national TV station's pronunciation guide is effectively the same as its BBC counterpart, except the word "Londonderry", in which the first six letters are silent.
I hope some of this proves helpful to visitors, writers or anyone else trying to navigate the confusing world of Irish history! On Friday I'll talk a bit more about writing about Ireland and her two resident countries, and next week I'll be posting some hints for writing about the Republic of Ireland (and there won't be a leprechaun in sight, I promise).