Birth dates are sourced in several ways. These include

  • Birth records from GRO Registers (or Birth Certificates supplied by the GRO)
  • Birth records transcribed by Leitrim Heritage Centre ( from GRO registers
  • Birth records supplied to the author (there are few of these in the collection)
  • Birth dates based on Baptismal Dates
  • Birth dates calculated from ages stated on Census records or on Death records
  • Birth dates estimated based on year of marriage, or the year of marriage of a child.

Calculated or Estimated Dates

A comparison of ages of individuals as stated on the 1901 Census of Ireland versus those on the 1911 Census will often show discrepancies, in some cases in excess of 10 years. We have to bear in mind that firstly people of those days were not as numerate as today, and secondly that in many cases they did not know their exact years of birth. An added complication was the introduction of Old Age Pensions in 1907 - there can be little doubt that some people added years to their ages in order to qualify. While the data supplied on the Census returns was never going to be used in determining eligibiilty for the Pension, there was an element of distrust that helped boost ages stated.

In many cases it will be found that the ages stated on death records were also wrong. Again we can take into account the numeracy factor, and also have to take into account the fact that in many cases the informant of a death was making a guess at the age of the deceased.

Birth years that were estimated purely on the year of the person's marriage, or even on the year of the marriage of one of their children were based on assuming that the person was at least 20 when married, and in the case of the marriage of the person's child, that that child was also at least 20 when married.

Other Birth Years

For all other Birth Year data, see links below.