What is the extent of poverty in the United States? Who are the poor in terms of age, race, ethnicity and gender?

The poverty rate in the United States today is roughly 13%.  This means that roughly 40 million Americans live in poverty.

To give you some idea as to what poverty means, a family of two parents and two kids is in poverty if it makes less than about $22,000 per year.   So the poverty line is pretty low.

For non-Hispanic whites, the percent in poverty was a bit under 9.  About 13% of Asians were in poverty, 23% of Hispanics and 24% of African Americans were poor.  All of these numbers are for 2008, the last year for which data are available.

28% of households with a woman and no husband are in poverty, 13% of those with a man and no wife.  5% of married couple households are in poverty.

The link below will at least give you information for age as well.