If you need to locate a person in custody, various resources can help. For state prisons, check the Department of Corrections Facilities by State.
The U.S. Bureau of Prisons (BOP) Inmate Locator provides information on federal inmates incarcerated since 1982.
US Bureau of Prisons Inmate Locator
To locate incarcerated individuals held in local jails, use the Local Jail Inmate Search or Inmate Search from Jail Guide.