Published Tuesday, 10 April 2012
Narrow Water Castle in Co Down. (© UTV)
The iconic building just outside Warrenpoint will represent the letter N in the collection, which makes up an alphabetic tour of the UK.
Environment Minister Alex Attwood has welcomed the inclusion of the historic site.
"Not only is it very appealing visually, it has its own history, not least in its defence from Viking invasions," said the SDLP minister.
"The built heritage in Northern Ireland are key jewels in our tourism industry. This is in recognition of one of those jewels, the Narrow Water Castle just outside Warrenpoint.
"By being reproduced on a stamp raises its profile and will lead to more tourists visiting this splendid coastal resort.
"In welcoming this announcement I and many others will also recall and remember the terrible events of the past close to this site."
Some of the other locations featured on the N-Z stamps include the White Cliffs of Dover, Manchester Town Hall, Stirling Castle and Tyne Bridge.
The stamps release on 10 April, after A-L launched last October.