This article focus to Define and Discuss on Prisons. All of the discussion are based on American Law perspective. Here discuss various types of prisons, they are Super‐maximum‐security prisons, Maximum‐security prisons, Medium‐security prisons, Minimum‐security prisons, Women’s prisons and Coeducational prisons. Here also briefly analysis on Exponential growth in the prison population, the level of incarceration, Racial disparities, Regional disparities, Prison overcrowding, Prison programs and the abolishment of parole.