The death penalty—also known as capital punishment—refers to the process of state and federal courts sentencing persons convicted of the most serious criminal offenses (capital offenses or capital crimes) to death. The specific crimes and circumstances for which the death penalty is a potential punishment (usually murder) are defined by state and federal statutes enacted by state legislatures and the United States Congress, respectively.

These death penalty or capital punishment statutes are often located in the penal or criminal code, and often in the same statute that defines a criminal offense such as murder. Twenty-two states and the District of Columbia do not have the death penalty as a potential punishment for any criminal offense.

In Illinois, the death penalty has been abolished. The state of Illinois does not impose capital punishment as a sentence for any criminal offense. This change came into effect when former Governor Pat Quinn signed legislation on March 9, 2011, repealing the death penalty. The law went into effect on July 1, 2011, converting existing death sentences to life imprisonment without the possibility of parole. Prior to its abolition, the death penalty in Illinois was regulated by state statutes, which outlined the specific crimes and circumstances that could result in a death sentence, typically for very serious offenses such as aggravated murder. However, since the repeal, no state statutes in Illinois provide for the death penalty, aligning the state with the other twenty-two states and the District of Columbia where capital punishment is not an available sentencing option.