Population projections are subject to a variety of factors
White people of European descent will no longer make up a majority of the US population by the year 2042 - eight years sooner than previous estimates.
The big change is among Hispanics and Asians whose share of the population is set to double to 30% and 9%.
The population is also ageing: by 2050 one in five residents will be aged 65 or over, up from one in nine today.
The US Census Bureau's latest projections are based on birth, death and current immigration rates.
The projections show that the US population is expected to rise from 305 million people to 439 million by 2050, but it will be a population that looks quite different both in age, race and ethnicity.
According to the census bureau's statistics, people who regard themselves as Hispanic, African-American, Asian, American Indian, Native Hawaiian and Pacific Islander will become the majority by 2042.
Officials had previously projected that this change would happen in 2050.
The new projections suggestion that by 2050, minorities will account for 54% of the population and non-Hispanic whites 46%, down from their current 64.7% share.
Immigration and higher birth rates among US minorities, especially Hispanics, are accelerating the demographic changes.
Hispanics will see their population nearly triple from 47 million to 133 million, causing their share of the population to increase from 15% to 30%.
Asians will also see a big increase, with their numbers growing from 16 million to 41 million.
Single-race Asians will account for 8% of the population and 9% including those of mixed race.
The black population, including those of mixed race, will show a slight increase from 14% to 15% of the total.
'Ageing baby boomers'
It is likely that the demographic changes will be experienced right across the country - and no longer confined to urban areas as in the past.
The population will also be ageing, with some 88 million people, predominantly white, being aged 65 and over.
The number of people over 85 years old will more than triple in the next 40 years, reaching 19 million.
"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, told the Associated Press.
"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, natural or man-made disasters.
The projections are also subject to changing cultural definitions and the way people see themselves.
The New York Times notes that in earlier eras Irish, Italian and Eastern European Jewish immigrants were not universally considered as whites.
Until the 1960s, Hispanics were not counted separately by the census and Asian Indians were classified as whites, the paper reports.
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