The Arizona Department of Corrections is a department of the state government of Arizona that imprisons adult men and women serving sentences for crimes that they have already been convicted of. (As opposed to county jails, which mostly incarcerate people who have not yet been convicted of a crime and are awaiting trial.)
Arizona state prisoners are housed in 10 state owned and operated facilities across the state, and 6 private facilities that are owned and operated by for-profit, non-governmental corporations. As of May 2018, 42,071 men and women were being held in Arizona prisons. Approximately 15% of these prisoners are held in for-profit prisons.
You can find the website for the Arizona Department of Corrections, including information on the current prison population and visitation information here.