Population figures:Some 70,000 people migrated to Ireland in the 12 months to April 2005, the highest annual immigration figure on record.
The estimated number of emigrants in the same period was 16,600 - a record low.
This resulted in a net migration figure of 53,400, compared with 31,600 in the 12 months to April 2004.
The figures, contained in the latest CSO report on population and migration statistics, confirmed the influence of shifting migration patterns on the population. In the year to April 2005, the population grew by 87,000 to 4.13 million. The figure is the highest on record since the census of 1861, which gave Ireland a population of 4.4 million.
The CSO said another factor in population growth was a doubling in the excess of births over deaths in the past 10 years.
The natural increase in the population (ie births less deaths) for the year ending April 2005 was 33,500. This compared to 16,600 in the 12 months to April 1994.
The figures show an increase in population across all age categories, including a significant rise in the elderly population. In April 2005, there were 111,300 people aged 80 years and over - a 17 per cent increase over April 2000.
Population growth was highest in the Dublin commuter belt area, with a 3.4 per cent rise between 2004 and 2005. The population in the midlands and southeast both rose by 2.6 per cent, while Dublin's population showed a mere 1.4 per cent rise - the lowest of all the regions.
CSO senior statistician Aidan Punch said the figures supported the thesis that there was an "overspill" of people from Dublin to neighbouring counties.
The west also showed a significant population increase of 3 per cent to 406,000 in April 2005.
Dublin accounted for 28 per cent of the population in 2005, with 1.16 million inhabitants.
