One sixth of people living in Preston were not born in the United Kingdom.
Estimates from the Office for National Statistics show that 17 per cent of the two areas' combined 139,000-strong population last year were born overseas .
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 23,000 people living in Preston last year who were born outside the UK, nearly half (48 per cent) were from South Asia.
Across England and Wales, the population born inside the EU has stabilised over the last 10 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 9.3m people born overseas lived in the UK last year – 14 per cent of the population.
There was a higher proportion of migrants among people of working age: 18 per cent.
Between 2008 and 2018, the greatest increase in the share of people born outside the UK was in South Bucks and Surrey Heath, where it rose by 15 per cent in both areas.
The sharpest fall was in Richmondshire, where it went down by seven per cent.