The city’s name is a point of political dispute, with unionists advocating the longer name, and nationalists advocating the shorter. A common attempt at compromise is to refer to the county as “Londonderry” and the city as “Derry”, but this is by no means universally accepted. Because of this, a peculiar situation arises as there is no common consensus either in politics or elsewhere as to which name is preferred; the city council is officially known as “Derry”, but the city is officially recognised as “Londonderry” by the Northern Ireland Executive and the UK government. Whilst road signs in the Republic of Ireland use “Derry”, alongside the Irish language translation “Doire”, road signs in Northern Ireland will always read (unless vandalised) “Londonderry”.
Here is the link. I hope someday to go.