You are correct. After a little more digging, I found this: "BJS’s official measure of the prison population is the count of prisoners under the jurisdiction

You are correct. After a little more digging, I found this: "BJS’s official measure of the prison population is the count of prisoners under the jurisdiction or legal authority of state and federal adult correctional officials (1,598,780 in 2011). The jurisdiction population count is reported in Prisoners in 2011, BJS website, NCJ 239808, December 2012. These prisoners may be held in prison or jail facilities located outside of the state or federal prison systems. The prison population reported in table 2 in this report is the number held in custody or physically housed in state (1,289,376 in 2011) and federal (214,774 in 2011) adult correctional facilities, regardless of which entity has legal authority over the prisoners (appendix table 1). This includes state and federal prisoners held in privately operated facilities. The difference between the number of prisoners in custody and the number under jurisdiction is the number of state and federal prisoners held in the custody of local jails, inmates out to court, and those in transit from the jurisdiction of legal authority to the custody of a confinement facility outside that jurisdiction." from http://bjs.ojp.usdoj.gov/content/pub/pdf/cpus11.pdf http://bjs.ojp.usdoj.gov/content/pub/pdf/cpus11.pdf