Irish Civil records are intact and these include all Births, Marriages and Deaths from 1864, although some early births may have missed registration. In addition, non-Catholic and Registry Office marriages were included in the registers from 1845.
Civil records can be searched in the Irish Civil BMD Index on familysearch, which is an index to these records. A new familysearch site has recently been launched which can be used as an alternative - see Familysearch Beta Website (This site is still under development and functionality can change from time to time)
Certs can then be ordered from the GRO using the references provided in the index record.
Also available online are the Irish 1901 and 1911 census (free) on the National Archives website. No other earlier complete Irish census returns have survived and only fragments of earlier ones for a few places survive.
For earlier dates church records will be required, and to start researching this you need to know two details : religion & location i.e. parish, town or townland (see addition details on Church records in the next post).
Some records are available on a free website IrishGenealogy - at the moment this website includes details for counties Carlow (Cofi), Kerry (RC & CofI), Diocese of Cork & Ross (RC) and parts of Dublin city & county (RC, CofI & Presbyterian). Additional RC records for Dublin and Cork are due to be added later in the year. The website also includes a sign-pointing index for counties Armagh, Cavan, Derry, Donegal, Fermanagh, Leitrim, Limerick, Mayo, Sligo, Tyrone and Wexford. Other areas are available on several subscription and pay-per-view websites.
Location of actual records depends mainly on the religion involved, but Catholic records are available on microfilm in the National Library in Kildare St, in Dublin (website :
http://www.nli.ie/), and most Church of Ireland records are available in the Representative Church Body Library in Rathfarnham (website :
http://ireland.anglican.org/library/).
There are also some useful extracted records on familysearch :
Births, 1864-1881
Marriages, 1845-1870
Deaths, 1864-1870 (not many included)