The 2010 Census counted nearly 600,000 more Hispanics than estimated in 28 states, the Pew Center said Tuesday.
The gap between the 2010 count and estimates of the Hispanic population by the Census Bureau were widest in states with relatively small Hispanic populations, Pew said.
It was more than 10 percent higher than expected in Alabama, Louisiana and Kansas.
"Hispanics are in some places growing faster than we had thought," said Pew demographer Jeffrey Passel. "This sort of broad pattern suggests immigration into these new areas was a bit higher."
Data released from 33 states indicated Hispanics accounted for 58 percent of population growth in the past decade.