When it comes to American Prisons, there are many variants. Prisons vary not only due to the difference in crimes committed but even based on the gender of the person committing the crime. It may even vary with the profession of the charged person.
If we remember, earlier a criminal was made sit inside a church and was asked to pray to God for forgiveness of the crimes committed by him, that was kind of a prison too. It is quite obvious that the prisons have come a long way since then. The prisons vary with the security levels of the inmates in the house and these security levels are as follows:
The inmates which are considered to be of no threat to common people are provided with minimum security facilities or Federal Prison Camps. These inmates enjoy a lot of freedom inside the jail compound. These have dormitory housing; the staff to inmate ratio is quite low as well. The parameter fencing is limited and sometimes is given a miss also. These are generally located near a military base or large institution thus the prisoners serve as labors for the base or institution.
These are also known as Federal Correctional Institution or FCI. These are generally dormitory or cubicle housing and have double parameter fencing. The staff to inmate ratio is higher than that of Federal Prison camps and the inmates are put into hard work.
These allow the prisoners to be free at daytime but at night, they have to sleep under the vigilant eyes of the security personnel. The border is fenced doubly and with an electronic detection system. The housing is generally of cell type, the work and treatment program is of broader array and the interior controls are quite strict as well.
Popularly known as United States Penitentiaries or USP, these are for violent offenders and lock inmates for 23 hours in a day. These prisons have reinforced fences or walls, the cell housing is of single or multiple occupants, and the staff to inmate ratio is the maximum as well.
Other than these four, there is a security level for serial killers. These inmates are given no freedom and treated harshly as well, an issue often raised by the various Human Rights organizations.