Capital punishment of a felon in the United States, in modern times, is employed rarely and only in cases involving murder. The history of U.S. capital punishment begins in the colonies under the laws of their mother countries and was carried over into U.S. law and the law of most of the U.S. states and territories. The methods of execution and the crimes subject to the penalty vary by jurisdiction and have varied widely throughout time. Some jurisdictions have banned it, others have suspended its use, but others are trying to expand its applicability. Since the reinstatement of the death penalty in 1976, there have been 1,129 executions in the United States as of October 2008. There were 42 executions in 2007.

Capital punishment is a controversial issue, with many prominent organizations and individuals participating in the debate. Arguments for and against capital punishment are based on moral, practical, religious, and emotional grounds. Advocates of the death penalty argue that it deters crime, improves the community by making sure that convicted criminals do not offend again, provides closure to surviving victims or loved ones, is a just penalty for their crime and that no prison has been able to prevent murderers from killing again. Opponents argue that the death penalty does not deter, does not save money, and that capital punishment cheapens human life and puts government who take guilty lives on the same low moral level as criminals who have taken innocent life.

Between 1973 and 1995, 67% of capital convictions in the United States were eventually overturned, mainly on procedural grounds of incompetent legal counsel, police or prosecutors who suppressed evidence, judges who gave jurors the wrong instructions and mass commutations by governors personally opposed to the death penalty. Among those whose sentences were overturned, seven percent were acquitted and ten percent were retried and re-sentenced to death. The remainder typically ended up with lesser sentences, up to and including life imprisonment.