Daily Archives: June 6, 2008

Post Coding Ireland

I hear the birds in the South of Ireland are chattering Post Codes once more. Let their music not fade into oblivion like a one hit wonder, but rise with a great crescendo to completion of the task. Postcodes are very handy. I know because I have one. Way up here in the cold and often forgotten part of the UK, are many towns and villages with a prefix of ‘Bally’. I live in one of them. Back in the days before we had post codes our mail took the tourist and scenic route via Ballycastle. Now with a Post code such detours are avoided.

Nowadays all my outgoing mail has a return address of my last name, house number and post code. I have in fact received Christmas Cards from the United States of America addressed to that return address. If for any reason I need to phone my bank or any utility company they ask first for my postcode and then the house number and finally ask me to verify my name. When travelling my luggage tags have only this return address.

Northern Ireland was the last part of the UK to be postcoded with all postcodes here beginning BT, a mnemonic of the capital city’s name. While Belfast was already divided into postal districts, rural areas known as townlands posed an additional problem, as (at the time) many roads were not named, and houses were not numbered. Consequently, many people living in such areas shared the same postal address, which is still the custom in the Republic of Ireland. Today the majority of roads in Northern Ireland are named with the odd exceptions in Co Fermanagh and most houses (even in rural areas) are allocated a number. Those that are not allocated numbers can be uniquely identified by a house name. An example is Bushmills, which begins with BT57.

The format of UK postcodes is generally:

A9 9AA

A99 9AA



AA99 9AA


where A signifies a letter and 9 a digit. It is a hierarchical system, working from left to right — the first letter or pair of letters represents the area, the following digit or digits represent the district within that area, and so on. Each postcode generally represents a street, part of a street, or a single premises. This feature makes the postcode useful to route planning software.

The part of the code before the space is the outward code or out code used to direct mail from one sorting office to the destination sorting office, while the part after the space is the inward code or in code used to sort the mail into individual delivery rounds. The outward code can be split further into the area part (letters identifying one of 124 postal areas) and the district part (usually numbers); similarly, the inward code is split into the sector part (number) and the unit part (letters). Each postcode identifies the address to within 100 properties (with an average of 15 properties per postcode), although a large business may have a single code


The population in the Republic of Ireland are well prepared for this type of system since vehicle registration has worked on a similar vein for several years. Surely incorporating the latter system would make the providing of Postal areas and districts an easier task.

What do you think?