States With the Largest Declines in Prisoner Populations

For years, the U.S. has topped global incarceration rates, warehousing more prisoners than any other country, including China. According to the Prison Policy Initiative, 1 in every 5 people in prison worldwide is incarcerated in the U.S.

But the U.S. prison population has been on the decline since its peak in 2009, according to a recent report by The Sentencing Project, a research and advocacy center based in Washington, D.C. The overall number of prisoners in the country reduced by 11% in the decade from 2009-2019, to 1.4 million people.

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Still, the gap between states' prisoner population numbers is wide, with the top state seeing a 43% reduction in prisoners between its peak in 2006 and 2019, while the bottom state is still peaking, with a 28% increase since 2014. According to the report, based on Bureau of Justice statistics data, all but four states saw a decrease in prison population levels since their peak. Of those states, however, 25 have seen reductions below 10%. The federal prison population, in contrast, saw a 20% decrease since its peak in 2011.

In nine states, Alabama, Alaska, California, Connecticut, Hawaii, New Jersey, New York, Rhode Island and Vermont, the prison population has been reduced by 30% or more since peak levels. Montana, Idaho, Nebraska and Kansas saw their highest population on record in 2019.

Nationally, the average annual decarceration rate was about 1.2%, making a significant reduction -- such as cutting the U.S. prison population in half -- a nearly 60-year endeavor at this rate.

Here are the 10 states with the greatest decreases in prison population from the peak year to 2019:

Kaia Hubbard is a graduate of the University of San Diego and is a yearlong News intern.