Led by California, 26 U.S. states reported decreases in their prison populations during 2011, according to the Justice Department's Bureau of Justice Statistics (BJS).
According to the BJS' report Prisoners in 2011, California saw the largest decline in its prison population, reporting 15,493 fewer prisoners in 2011 than in 2010. New Jersey, New York, Michigan, Florida, and Texas each had population decreases of more than 1,000 prisoners in 2011.
Also See: US Jail Population Falls Again
Among the states in which prison populations increased, Tennessee and Kentucky both added more than 1,000 inmates in 2011.
Overall, the total U.S. prison population declined for the second consecutive year during 2011, falling to fewer than 1.6 million inmates or 15,023 fewer inmates than in 2010. The imprisonment rate dropped to 429 inmates per 100,000 residents in 2011. The U.S. imprisonment rate has been falling since 2007 when 506 of every 100,000 residents was in state, local or federal prisons or jails.
Nationwide, 19,584 more people were released from prison (688,384) than were admitted (668,800) during 2011.
The net decline in U.S. prison population was due to a 21,614 inmate decrease in state prisoners from 2010 to 2011. That decrease, however, was offset by an increase of 6,591 new prisoners in federal prisons, a 3.1% increase from 2010 to 2011.
A full 72% of that 21,614 inmate decrease in state prisoners came in California, which reduced its state prison population by 15,493 inmates from 2010 to 2011.
How Did California Do That?
California's drastic decrease in its state prison population is a result of its Public Safety Realignment policy.
Ruling 5-4 that gross overcrowding in California's state prisons violated the 8th Amendment, the U.S. Supreme Court in May 2011, ordered the state to reduce its state prison population by more than 30,000 inmates.
In response, California enacted its Public Safety Realignment Act, which shifts responsibility for the incarceration, treatment, and supervision of persons convicted of certain nonviolent, non-serious, non-sex crimes from the state to its 58 counties.
Since implementation of the Public Safety Realignment Act began on October 1, 2011, California's newly convicted non-violent, low-level inmates have been transferred from state prisons to county-operated jails and probation programs. The law also encourages the counties to increasingly employ evidence-based alternatives to prison, including work-release and electronically supervised release programs.
In fact, in its passage of the Public Safety Realignment Act, the state legislature warned counties not to respond by simply building new prisons, noting that "building and operating more prisons to address community safety concerns is not sustainable, and will not result in improved public safety."