Ireland does not have postal codes, but there are some postal districts in Dublin with numbers ranging from 1 to 24. You would ideally need to know the postal district for the area you are posting to, though in some cases the letter would get to its destination just by the area name. Many of the area names or street names would be distinctive enough for the letter to reach the destination. O'Connell Street is Dublin's main street, and it is in what is known as Dublin 1, but either of the following would get it there:
Mr J. Smith
1 O'Connell Street
Dublin 1
Mr J. Smith
1 O'Connell Street
Dublin
Ireland
Names of areas like Donnybrook, Ballsbridge, Rathmines, Artane, Cabra, Inchicore and many others could easily be put on a letter and still have the particular address found by the postal service without the postal district.
So something like these would work:
Mr J. Smith
1 Main Street
Donnybrook
Dublin
Ireland
Mr J. Smith
1 Main Street
Donnybrook
Dublin 4
Ireland
-------------------
Mr J. Smith
1 Main Street
Cabra
Dublin
Ireland
Mr J. Smith
1 Main Street
Cabra
Dublin 7
Ireland
However, if it all possible, find out the postal district of the area you are writing to. Once you have that, your letter should have no problems in reaching its destination.
The web address of the Dublin Historical Society is: www.dublinohiohistoricalsociety.org
The web address of the Dublin Historical Museum is: http://www.dublinrodeo.org
The address for the Mansion House is: Dawson Street, Dublin 2, County Dublin, Ireland. The address shown, will be able to receive any enquires you may have.
The address for the luxury hotel the Fitzwilliam Hotel in Dublin is St. Stephens Green, Dublin 2, Ireland. The Fitzwilliam is located by Dublin's finest shopping avenue.
The address of the Dublin Library is: 200 Civic Plaza, Dublin, 94568 2619
The address for Bewleys hotel in Dublin is Marrion Road, Ballsbridge, D4, Co, Dublin City, Ireland. This hotel is near the Dublin Airport and will be a very easy access for people who are visiting Dublin.
The address of The Morrison Hotel in Dublin is Ormond Quay, Dublin, Co. Dublin 1, Ireland. One can also contact at their number which is +353 1 887 2400.
Dublin Ferry Port Alexandra Road Dublin 1 Ireland.
The Lynams Hotel is located in Dublin, Ireland. The postal address listed on the official Lyndams website for this hotel in Dublin is 63/64 O'Connell Street, Dublin 1, Ireland.
That will depend on where in Dublin you are. See the link below.
The address of the Dublin Historical Society is: Po Box 2, Dublin, OH 43017
The address of the Dublin Laurens Museum is: 311 Academy Ave, Dublin, GA 31021