List of rampage killers in the United States

This is a list of mass or spree killers in the United States. A mass murderer is typically defined as someone who kills three or more people in one incident, with no "cooling off" period, not including themselves. A mass murder typically occurs in a single location where one or more persons kill several others.

Specific notable subtypes of mass murder, including politically motivated crimes, workplace killings, school attacks and familicides, have their own lists.

This list does not include serial killers, members of democidal governments, or major political figures who orchestrated such actions.

Abbreviations and footnotes
W – A basic description of the weapons used in the murders
 * F – Firearms and other ranged weapons, especially rifles and handguns, but also bows and crossbows, grenade launchers, flamethrowers, or slingshots
 * M – Melee weapons, like knives, swords, spears, machetes, axes, clubs, rods, stones, or bare hands
 * O – Any other weapons, such as bombs, hand grenades, Molotov cocktails, poison and poisonous gas, as well as vehicle and arson attacks
 * A – indicates that an arson attack was the only other weapon used
 * V – indicates that a vehicle was the only other weapon used
 * E – indicates that explosives of any sort were the only other weapon used
 * P – indicates that an anaesthetising or deadly substance of any kind was the only other weapon used (includes poisonous gas)