As the US struggles to avoid a recession, unemployment is over nine per cent and the number of Americans living in poverty has risen for the fourth year in a row to just over 15 per cent of the population.
Hispanic and black communities are once again worst affected with over a quarter living in poverty.
The US definition of poverty is an annual income equal to or less than approximately 22,000 dollars (16,000 euros) for a family of four.
Anti-poverty campaigners seized on the data to try to defend social welfare programmes against government cuts and a right-wing ideological offensive.
"The Census data highlight the serious hardship facing many American families in the current economic crisis," said Elizabeth Grayer of women's campaign group Legal Momentum. "The data indicate increased poverty and a continuing gender poverty gap in the United States, facts that underscore the need for a social safety net that is accessible and adequate."
"The 40.7 per cent poverty rate for solo mother families was 68 per cent greater than
the 24.2 per cent rate for solo father families," a Legal Momentum memo said.
The data comes as US President Barack Obama makes his case for a 450-billion-dollar job creation plan.
Speaking in Colombus, Ohio, yesterday, he said the bill would create jobs for tens of thousands of construction workers in Ohio alone.
The bill has come under fierce opposition from the Republican Party, which says it is more about Obama winning votes ahead of the Presidential elections than jobs for Americans.
As the Republicans control the House, he will in any case need to win some Republican approval if the bill is to be pushed through.