Caucasian people are projected to no longer be the majority race in the United States by the year 2042.
The US Census Bureau's latest figures - based on birth, death and immigration rates - suggest that minorities will soon make up 55% of the population.
Hispanics, who now make up about 15% will, it says, account for 30% by 2050.
It is projected that black people will make up 15%, a small increase, while Asians will grow from 4 to 9%.
Caucasian non-Hispanics currently make up about two-thirds of the population, but only 55% of those younger than five.
It is likely the demographic changes will be experienced across the country - and no longer confined to urban areas as in the past.
Overall, the US population is expected to rise from 305 million people to 439m by 2050.
"The white population is older and very much centred around the ageing baby boomers who are well past their high fertility years," William Frey, a demographer at the Brookings Institution think tank, says.
"The future of America is epitomised by the young people today. They are basically the melting pot we are going to see in the future."
The Census Bureau points out that its projections are subject to big revisions, depending on immigration policy, cultural changes and natural or manmade disasters.