Manslaughter is the unlawful killing or homicide of a human being without the premeditation or malice (malice aforethought) required for the criminal offense of murder. Many states have two types of manslaughter: (1) voluntary manslaughter—the defendant intended to kill the victim, but did so in self-defense, or in the heat of passion and without premeditation, or the defendant was insane and did not understand that the killing was wrong; and (2) involuntary manslaughter—the defendant negligently or recklessly caused the death of another person—such as when a person is intoxicated while operating a motor vehicle and causes an accident that results in the death of another person.

Some states do not have separate criminal offenses for voluntary and involuntary manslaughter—these states may have the offense of manslaughter and identify certain aggravating factors that may enhance the penalties upon a conviction for manslaughter. Manslaughter is a felony offense and may be punished by a lengthy prison term. Manslaughter laws are generally located in a state's statutes—often in the penal or criminal code.

In Idaho, manslaughter is defined under Idaho Code § 18-4006. The state recognizes both voluntary and involuntary manslaughter. Voluntary manslaughter occurs when a person unlawfully kills another human being without malice aforethought, either upon a sudden quarrel or heat of passion. Involuntary manslaughter, on the other hand, is when the killing is unintentional and occurs during the commission of an unlawful act not amounting to a felony, or in the commission of a lawful act which might produce death, in an unlawful manner, or without due caution and circumspection. Manslaughter in Idaho is considered a felony and can result in significant prison time. The specific circumstances of the offense, such as the use of a vehicle or other aggravating factors, can influence the severity of the penalties imposed upon conviction.