Prisons and jails added more than 42,000 inmates last year, the largest increase since 2000.
The total number of people incarcerated by federal or state authorities in the year ending June 30, 2006, was roughly 1.6 million, the government said Wednesday. That translated to a 2.8 percent increase from the previous year, due to people being put in prison at a faster rate than those released.
Overall, the total number of people behind bars, including those held in local jails, was more than 2.2 million, according to the Justice Department's Bureau of Justice Statistics.
Forty-two states and the federal system reported increases, with the largest jumps in Idaho (13.7 percent), Alaska (9.4 percent) and Vermont (8.3 percent). Eight states had declines, led by Missouri (down 2.9 percent), and Louisiana and Maine (both down 1.8 percent).
The number of federal prisoners increased by 3.6 percent to reach 191,080.
Nearly 6 out 10 people behind bars nationwide were black or Hispanic.
"Once again, communities of color are paying for our troubled criminal justice policies," said Jason Ziedenberg, executive director of the Justice Policy Institute. "The population increase in the already overburdened prison system indicates an alarming growth that should not go unchecked."