A nation's prison system holds people who have been convicted by the courts and sentenced to a term of imprisonment. Offenders in the United States may be placed in a state or in a federal correctional facility. If they are sentenced for less than one year, they will be held in a local or county jail. Other factors that determine which type of penal institution an individual is sent to include the crimes for which he or she has been convicted and his or her sex, age, mental health, and physical health. Juvenile offenders, unless they are tried as adults, are held separately from adult criminals in juvenile detention centers. Since the 1980s, the prison population in the United States has increased dramatically. Between 1980 and 1998 alone, it “ballooned from 329,821 to 1,302,019—a rise of 295 percent”—and as the population continues to rise beyond two million, “there is little ...