Most people who spend time in jail, however, do so in larger institutions. About 20 million people are admitted to the nation's jail each year. Some jail inmates stay for as little as a day. While others serve extended periods of time. Driving under the influence is the most common charge for jailed adults forty-five years of age or older. Drug violations accounts for twenty-two percent of those in jail. Most people processed through the country's jail are members of minority groups (fifty-eight percent) with forty-one point three percent of jail inmates classifying themselves as black, fifteen point one percent Hispanic, and one point six percent as other minorities. Forty-two percent of jail inmates classify themselves as white, eighty-eight point six percent are male inmates.
Prison on the other hand is a state or federal confinement facility that has custodial authority over adults sentenced to confinement. The prison system consist of high-security prisons for long-term, high-risk cases, one or more medium-security institutions for offenders who are not high-risk and one or two institutions for young adults (generally under the age 25). Some are specialized mental hospital-type security prisons for mentally ill and some others are open-type institutions for low-risk, non violent inmates.
Maximum-custody prison tend to be massive old prisons with large inmate populations. Such institutions provide tight security which is characterized by high fences, thick walls, secure cells, gun towers, and armed prisons guards. Maximum-custody prisons tend to locate cells and other inmate living facilities at the center of the institution and place a variety of barriers about the living area and the institution's outer perimeter. .
Prisoners, once in the correctional system, are classified according to local procedures and are assigned to confinement facilities & treatment programs. The imposition of a criminal sanction by a judicial authority must occur before a person gets incarcerated.