The American Prison System

In 1841, Dorothea Dix discovered that prison conditions were, in her opinion, inhumane. Prisoners were chained naked, whipped with rods. Others, criminally insane, were caged, or placed in cellars, or closets. She insisted on changes throughout the rest of her life. While focusing on the insane, her comments also resulted in changes for other inmates. At the beginning of 2008, more than 1 in 100 adults in the United States were in prison or jail. Total US incarceration peaked in 2008. Total correctional population (prison, jail, probation, parole) peaked in 2007. If all prisoners are counted (including juvenile, territorial, ICE, Indian country, and military), then in 2008 the US had around 24.7% of the world's 9.8 million prisoners.

In 2008, approximately one in every 31 adults (7.3 million) in the United States was either behind bars or being monitored (probation and parole). In recent decades the U.S. has experienced a surge in its prison population, quadrupling since 1980, partially as a result of mandatory sentencing that came about during the "War on Drugs."

As of the 2007. Census of Juveniles in Residential Placement (CJRP), conducted by the Office of Juvenile Justice and Delinquency Prevention, 86,927 youths were held in juvenile facilities. As of 2009, the three states with the lowest ratios of imprisoned people per 100,000 population are Maine (150 per 100,000), Minnesota (189 per 100,000), and New Hampshire (206 per 100,000). The three states with the highest ratio are Louisiana (881 per 100,000), Mississippi (702 per 100,000) and Oklahoma (657 per 100,000).

A 2005 report estimated that 27% of federal prison inmates are noncitizens, convicted of crimes while in the country legally or illegally However, federal prison inmates account for six percent of the total incarcerated population; noncitizen populations in state and local prisons are more difficult to establish.