Total Number of Adults Incarcerated in US Prisons and Jails, 2015
"At yearend 2015, an estimated 2,173,800 persons were either under the jurisdiction of state or federal prisons or in the custody of local jails in the United States, down about 51,300 persons compared to yearend 2014. This was the largest decline in the incarcerated population since it first decreased in 2009. By yearend 2015, the number of persons incarcerated in state or federal prisons or local jails fell to the lowest level observed since 2004 (2,136,600) (not shown).
"Declines in both the U.S. prison (down 2.3%) and local jail (down 2.2%) populations contributed to the decrease in the incarcerated population during 2015. However, 69% of the decline in the incarcerated population was due to the drop in the number of persons incarcerated in state or federal prisons (down 35,500). One jurisdiction, the Federal Bureau of Prisons, accounted for 40% of the decrease in the U.S. prison population during the year. By the end of 2015 (1,526,800), the U.S. prison population fell to a level similar to 2005 (1,525,900)."