Warden: The Keeper in a prison
One becomes a charge, when charged with a crime.
When one is found guilty, they become a convicted person (CONVICT or CON)
As such, they are a charge of the state, or a ward of the states custody.
Thus a Warden is a terminology of the one who watches over them.
At one time all Correctional Officers were Wardens by name. The Head Warden of the Jail, or Prison was known as the Chief Warden.
Sheriffs manned the Jails and were usually rotated every 6 mo in and out of the Jail to Patrol. This caused a shortage of man power as society grew and more officers were needed to combat crime.
On or about 1973 -1975, Corrections was developed as an alternative solution of those who worked in the jails and prisons and not in patrol. This became the new wave in terminology, since the job of a prison and Jail was REHABILITATION.
Many Departments were taken out from under the Sherriff, they were put under the Department of Rehabilitative Service. Rehabilitative Services was then placed as a Division, to function under the Sheriff or City Police Chief, as a separate entity, dealing with an inmates path to Rehabilitation upon conviction and a road mapped out, to make it in society as a member, rather then a criminal.
Today, many departments have the Correctional Officers as a force of Corrections. The Sheriffs as Sheriffs and Police as Police.
The head of Corrections, is a Warden, or in many Jails the Head of Corrections.
Within the states their is a Corrections Administrator and Correctional Officers, with a Warden, designated to oversee the individual facilities operations.
Many prisons have 2-3 Wardens. The head of the Prison, the assistant Warden over population and another over segregation and Health care.