Nearly one in every 33 people living in Caerphilly County Borough were born outside the UK, figures show, far below the average for England and Wales.
Estimates from the Office for National Statistics (ONS) show that only 3% of the areas’ 181,000-strong population last year were born overseas, up 1% from a decade earlier.
The figures are based on the Annual Population Survey, and count people living at private addresses and students in halls of residences whose parents are based in the UK. They exclude people living in communal buildings such as hostels or hotels.
Of the 6,000 people living in Caerphilly last year who were born outside the UK, most (67%) were from the European Union.
Across England and Wales, the population born inside the EU has stabilised over the last ten years, while the share born outside the EU increased gradually.
Rob McNeil, the deputy director of the Migration Observatory at the University of Oxford, said uncertainties surrounding the UK’s withdrawal from the trading bloc have made the country a less attractive destination for EU citizens.
He described a “lack of clarity” about their status as residents and workers after Brexit, with the falling value of the pound meaning that their potential earnings in the UK are worth less than in recent years.
Despite this general trend, Ann Blake of the Centre for International Migration at the ONS said population patterns differed at a local level.
The areas with the highest proportions of non-UK born populations were in London. They made up about half of all people in Brent, Westminster, and Kensington and Chelsea.
The ONS estimates that some 9.3 million people born overseas lived in the UK last year – 14% of the population.
There was a higher proportion of migrants among people of working age: 18%.