Dublin postal districts are used by the Ireland's postal service, known as An Post, to sort mail in the Dublin area. They appear with one or two digits appearing at the end of addresses, e.g:
British Embassy 29 Merrion Road Ballsbridge Dublin 4Odd numbers are used for addresses on the north side of the River Liffey, while even numbers are on addresses on the south side. The term 'Dublin 4' is used colloquially in the Republic to refer to the country's middle class liberal establishment.
Similar schemes were used in cities in other European countries until they adopted a national postcode system in the 1960s and '70s. However, Ireland did not follow suit, and An Post did not introduce automated sorting machines for mail until the 1990s. By then, the introduction of new technology, known as Optical Character Recognition (OCR), meant that machines could 'read' whole addresses as opposed to just postcodes, so An Post argued that a national postcode system was unnecessary. Consequently, mail to addresses in the rest of the Republic does not require any digits after the address, eg:
World Wide Web Marketing Ltd. 4/5 High Street, GalwayHowever, the Communications Regulator in Ireland is considering the introduction of such a system in the light of the liberalisation of postal services, and the end of An Post's monopoly.
