While 832 counties had a statistically significant increase in the school-age poverty rate, 10 counties saw the rate drop significantly, statisticians said.
The bureau released its Small Area Income and Poverty Estimates, which are among the factors used to determine federal aid to local schools. The estimates combine information from the bureau's American Community Survey, the 2000 and 2010 censuses, federal income tax filings and applications for federal nutrition assistance.
The bureau said there was a significant increase in poverty among children aged 5 to 17 in 26 percent of the counties. The bureau compared 2011 with 2007, the last year before the recession began.
A total of 83 counties had increases in school-age poverty between 2010 and 2011, while 23 had declines.