More than one in 10 people in the Republic has lived abroad for at least a year, usually in Britain, according to the latest Central Statistics Office figures.
The report shows that slightly more than 400,000 people - 11 per cent of the population - had spent a year or more elsewhere before resuming residence in time to be included in the 1996 Census. Almost a third of the total returned during the years 1991 to 1996.
Three-quarters of those included in the category lived in Britain before coming to the Republic. Nine per cent came from the US, while 7 per cent had lived in an EU country other than Britain. The migrants are also more likely to be females, accounting for 208,000 of the total, than male (195,000).
The figures - which analyse birthplace, normal residence and migration based on the census returns - also show that of the 40,000 who moved to the Republic in the year before the census, 22,000 had been born outside the State. The dominant age category - four in 10 of those arriving in the year previously - is 20-29.
Ninety-three per cent of all the Republic's residents were also born in the State. Of those born elsewhere, England and Wales account for 139,000, or 4 per cent.