In the United States, the law for murder varies by jurisdiction. In many US jurisdictions there is a hierarchy of acts, known collectively as homicide, of which first-degree murder and felony murder are the most serious, followed by second-degree murder and, in a few states, third-degree murder, which in other states is divided into voluntary manslaughter, and involuntary manslaughter such as reckless homicide and negligent homicide, which are the least serious, and ending finally in justifiable homicide, which is not a crime. However, because there are at least 52 relevant jurisdictions, each with its own criminal code, this is a considerable simplification.^[7]

Sentencing also varies widely depending upon the specific murder charge. "Life imprisonment" is a common penalty for first-degree murder, but its meaning varies widely.^[8]

Capital punishment is a legal sentence in 27 states,^[9][10] and in the federal civilian and military legal systems, though 8 of these states and the federal government have indefinitely suspended the practice. The United States is unusual in actually performing executions,^[11] with 34 states having performed executions since capital punishment was reinstated in 1976. The methods of execution have varied, but the most common method since 1976 has been lethal injection.^[12] In 2019 a total of 22 people were executed,^[13] and 2,652 people were on death row.^[14]

The federal Unborn Victims of Violence Act, enacted in 2004 and codified at 18 U.S. Code § 1841,^[15] allows for a fetus to be treated as victims in crimes. Subsection (c) of that statute specifically prohibits prosecutions related to consented abortions and medical treatments.^[15]