The numbers highlight sweeping changes in the nation's racial makeup.
"This is an important landmark," said Roderick Harrison, a former chief of racial statistics at the Census Bureau who is now a sociologist at Howard University. "This generation is growing up much more accustomed to diversity than its elders."
Minorities increased 1.9 percent to 36.6 percent of the total U.S. population, lifted by prior waves of immigration that brought in young families and boosted the number of Hispanic women in their prime childbearing years.
But the annual rates of growth for Hispanics and Asians fell sharply to about 2 percent.
The slowdown is shifting notions on when the tipping point in U.S. diversity will come - the time when non-Hispanic whites become a minority. After 2010 census results suggested a crossover as early as 2040, demographers now believe the pivotal moment may be pushed back several years.
Growth rates for blacks stayed flat at 1 percent.
Of the 30 large metropolitan areas showing the fastest Hispanic growth in the previous decade, all showed slower growth in 2011 than in the peak Hispanic growth years of 2005-2006, when the construction boom attracted new migrants to low-wage work.
Pointing to a longer-term decline in immigration, demographers believe the Hispanic population boom may have peaked.
California, along with Hawaii, New Mexico, Texas and D.C., have minority populations that exceed 50 percent.
The Associated Press contributed to this report.