Worst mass murders in the United States since 1945

This a list of the 40 worst intentional acts of mass murder in the United States since 1945. Taken from Wikipedia’s “List of disasters in the United States by death toll” article. Note that incidents of negligent homicide, drunk drivers and manslaughter have been excluded from here as that isn’t the same as murder (ie deliberate vs unintentional). I also sorted some of them out by weapon if multiple ones were used. Note that I also included some that happened outside the United States, such as Jonestown and two bombings in Beirut, Lebanon because they still were attacks on the United States and resulted in some of the greatest losses of American life in recent history.

1.) September 11 attacks - 2,996 dead
2.) Jonestown massacre - 918 dead (907 from cyanide, 7 by gunfire, 4 by stabbing)
3.) USS Indianapolis (CA-35) - 879 dead (torpedoed and sunk by a Japanese I-58 submarine) (I added this one as a bonus)
4.) 1983 Beirut Barracks bombing - 307 dead
5.) Pan Am Flight 103 - 270 dead
6.) 1998 United States embassy bombings - 224 dead
7.) EgyptAir Flight 990 - 217 dead
8.) Oklahoma City bombing - 168 dead
9.) Our Lady of the Angels School fire - 95 dead
10.) Waco siege - 88 dead (including 2 unborn and 4 ATF agents) (33 by fire, 32 by gunfire, 18 undetermined, 4 by blunt force and 1 by stabbing)
11.) Happy Land fire - 87 dead
12.) 1983 United States embassy bombing in Beirut - 64 dead
13.) 1992 Los Angeles riots - 63 dead (40 by gunfire, including 5 by police, 23 by other causes; 1 by strangulation, 2 stabbed, 8 vehicle-related, 2 from unknown blunt force-related injuries, 2 were beaten to death, 3 from fire, 3 unknown, 1 from a fall and 1 from a heart attack)
14.) 2017 Las Vegas shooting - 59 dead
15.) Orlando nightclub shooting - 50 dead
16.) USS Iowa turret explosion - 47 dead
17.) Continental Airlines Flight 11 - 45 dead
18.) United Airlines Flight 629 - 44 dead
19.) Attica prison riot - 44 dead (39 by gunfire as the inmates held 42 civilians hostage with knives and other makeshift weapons; the New York State Police troopers threw tear gas and fired non-stop for about two minutes into the smoke, killing 29 inmates and 10 hostages, including 9 correctional officers; only 5 were by inmates, including one correctional officer and four other inmates who were subjected to vigilant killings prior to the riots; the officer killed by inmates was Officer Quinn, who had been killed by blunt force injuries to his skull and the other four inmates were stabbed to death with shanks)
20.) Pacific Southwest Airlines Flight 1771 - 43 dead (5 dead by gunfire)
21.) Maury County jail fire - 42 dead
22.) St. Elizabeth’s hospital fire - 41 dead
23.) Heaven’s Gate (religious group) - 39 dead (all died from mixing Phenobarbital with apple sauce or pudding and washing it down with vodka and securing plastic bags around their heads, including Applewhite, the cult leader)
24.) USS Liberty incident - 34 dead (killed by torpedos and fighter jet missiles; deliberately killed them, but a case of mistaken identity, supposedly)
25.) Virginia Tech shooting - 33 dead
26.) UpStairs Lounge arson attack - 32 dead
27.) Sandy Hook school shooting - 28 dead
28.) Sutherland Springs church shooting - 27 dead
29.) Dorothy Mae apartments fire - 25 dead
30.) Luby’s shooting - 24 dead
31.) San Ysidro McDonald’s massacre - 23 dead
32.) University of Texas massacre - 18 dead (16 by shooting, 2 by stabbing)
33.) Beltway sniper attacks - 17 dead
34.) Stoneman Douglas High School shooting - 17 dead
35.) USS Cole bombing - 17 dead
36.) Ronald Gene Simmons - 16 dead (8 by strangulation/drowning in a rain barrel, 8 by gunfire)
37.) 2015 San Bernardino attack - 16 dead
38.) Edmond post office shooting - 15 dead
39.) Columbine High School massacre - 15 dead
40.) West Fertilizer Company explosion - 15 dead

Here’s a more detailed analysis of the 12 deadliest ones (excluding USS Indianapolis), which took a ton of research for me to get.

September 11 attacks
2,996 dead, 6,000+ wounded
Date: September 11, 2001
Target(s): World Trade Center (North and South Towers), The Pentagon, a field in Pennsylvania and public transportation (planes)
Location(s): Manhattan, New York; Stonycreek Township, Pennsylvania; The Pentagon in Arlington County, Virginia
Weapon(s): Knives (7 or 9 dead) hijacked commercial airliner jets (2989 or 2,987 dead)
Perpetrator(s): Waleed M. Al-Shehri, Wail M. Al-Shehri, Mohamed Atta, Abdulaziz Al-Omari, Satam M. A. Al-Suqami, Marwan Al-Shehhi, Fayez Rashid Ahmed Hassan Al-Qadi Banihammad, Mohand Al-Shehri, Hamza Al-Ghamdi, Ahmed Al-Ghamdi, Khalid Al-Mihdhar, Majed Moqed, Nawaf Al-Hazmi, Salem Al-Hazmi, Hani Hanjour, Ahmad Ibrahim A. Al-Haznawi, Ahmed Al-Nami, Ziad Samir Jarrah, and Saeed Al-Ghamdi

Jonestown massacre
918 dead, 35 wounded
Date: November 18, 1978
Target(s): an air strip of land, The Peoples Temple Agricultural Project, The Peoples Temple of the Disciples of Christ’s headquarters building in Georgetown
Location(s): Port Kaituma, Georgetown and Jonestown, Guyana
Weapon(s): Cyanide (907 dead), Guns (7 dead), Knives (4 dead)
Perpetrator: Jim Jones, Annie Moore (Jonestown massacre), Sharon Amos (Georgetown killings; she killed two of her children with a knife before having her 21-year-old daughter kill her with a knife before killing herself), Larry Layton,
Joe Wilson, Thomas Kice Sr., Ronnie Dennis, and approximately 5–6 additional Peoples Temple members (Cessna/Twin Otter attack at Port Kaituma)

1983 Beirut barracks bombings
307 dead (including 241 US military personnel), 150+ wounded (including 115 Americans)
Date: October 23, 1983
Target(s): United States Marine Corps barracks at the Beirut Airport and the Drakkar barracks of the French 1st Parachute Chasseur Regiment and 9th Chasseur Regiment
Location(s): Beirut and Ramlet al Baida, Lebanon
Weapon(s): two truck bombs
Perpetrator(s): Ismalal/Ismail Ascari (media sources have identified his name as being spelled either as “Ismalal Ascari” or “Ismail Ascari”, depending on your source) and another unidentified bomber.

Pan Am Flight 103
270 dead (259 died in the plane, 11 died on the ground)
Date: December 21, 1988
Target(s): commercial aircraft
Location: Lockerbie, Scotland (landed)
Weapon: Bomb, Plane
Perpetrator: Abdelbaset Al-Meghrani

1998 United States embassy bombings
224 dead (12 Americans killed), 4,000+ wounded
Date: August 7, 1998
Target(s): United States Embassy in Dar es Salaam, Tanzania and the United States Embassy in Nairobi, Kenya
Location(s): Nairobi, Kenya and Dar es Salaam, Tanzania
Weapon(s): two truck bombs
Perpetrator(s): Mohamed Rashed Daoud Al-Owhali and Hamden Khalif Allah Awad

EgyptAir Flight 990
217 dead
Date: October 31, 1999
Target: commercial airliner
Location: Atlantic Ocean, about 60 miles south of Nantucket Island, Massachusetts (landed)
Weapon: Plane, Water/Drowning (Ocean)
Perpetrator: Gameel Al-Batouti

Oklahoma City bombing
168 dead, 680+ wounded
Date: April 19, 1995
Target: Alfred P. Murrah federal building
Location: Oklahoma City, Oklahoma
Weapon: truck bomb
Perpetrator: Timothy McVeigh

Our Lady of the Angels School fire
95 dead
Date: December 1, 1958
Target: Our Lady of the Angels School
Location: Chicago, Illinois
Weapon: Matches/Fire
Perpetrator: A 10-year-old boy

Waco siege
88 dead (including 2 unborn and 4 ATF), 14 - 28 ATF agents wounded (sources vary), only about 50 Branch Davidians survived the siege and fire (with only 9 surviving the fire) (exact number of injuries unknown, nor is it known how many of them were injured or possibly escaped without injuries)
Date(s): February 28 - April 19, 1993
Target: Mount Carmel Center
Location: Waco, Texas
Weapon(s): Fire (33 dead), Guns (32 dead), Undetermined (18 dead), Blunt Force (4 dead), Stabbing (1 dead)
Perpetrator(s): David Koresh and his followers / ATF

Happy Land fire
87 dead, 6 wounded
Date: March 25, 1990
Target: Happy Land social club
Location: Bronx, New York
Weapon: Fire (Gasoline)
Perpetrator: Julio Gonzalez

1983 United States embassy bombing in Beirut
64 dead, 120 wounded
Date: April 18, 1983
Target: United States Embassy in Beirut, Lebanon
Location: Beirut, Lebanon
Weapon: car bomb
Perpetrator(s): Unknown. Imad Mughniyah was alleged to have responsibility for this particular bombing, however this has been disputed. According to his Wikipedia article:

“U.S. and Israeli officials have implicated Mughniyeh of many terrorist attacks, primarily against American and Israeli targets. These include 18 April 1983 bombing of the United States embassy in Beirut, Lebanon, which killed 63 people including 17 Americans whom among them were 7 CIA officers which included Robert Ames the head of Near East Division. Agreement is not entirely universal on Mughniyeh's involvement, and Caspar Weinberger, the Secretary of Defense at the time of the attack, told PBS in 2001, "We still do not have the actual knowledge of who was directly behind and responsible for the bombing of the American Embassy in Beirut, Lebanon and we certainly didn't then."”

1992 Los Angeles riots
63 dead, 2,383 wounded
Date(s): April 29 - May 4, 1992

Target(s): Supermarkets and other business stores (including video stores, shoe stores, auto part stores, check cashing stores, five and dime stores, etc.), city streets and intersections, residential neighborhoods, parking lots, city squares, gas stations and liquor stores, apartment complexes, etc.

Location(s): Los Angeles County, California; 3 died in San Diego (South Park); 1 in Fresno (Del Rey)

Weapon(s): 40 by gunfire (including 5 who were shot by police), 23 by other causes; including 1 by strangulation, 2 stabbed, 8 vehicle-related, 2 from unknown blunt force-related injuries (unclear if they had been beaten or bludgeoned), 2 were beaten to death, 3 from fire, 3 unknown, 1 from a fall and 1 from a heart attack

Perpetrator(s): Odell Whitley Jr., Leonard Hampton and another unnamed teen(?) (Lucie Maronian; stabbed), Aniceto Barajas (Jose L. Garcia; shot), Mario E. Olivera (George Alvarez; beaten), Three suspects, including a 17-year-old (Paul Horace; shot), Akim Dashawn Gilmore (Alfred V. Miller; shot), Traville J. Craig (Elias G. Rivera; unknown blunt force-related injuries), Fidel Ortiz and Leonard Sosa (Wallace Tope; beaten), three men, two of whom were teenagers (Matthew D. Haines; shot), 15-year-old boy (Juana Espinosa; shot), Samiee Farzan (Imad Sharaf; fire), Andre Webb and Lavelle "Frog" Williams (Charles Orebo; shot), most others no charges were ever brought against, because they were either unrelated to the riot (one person died with a cigarette in his mouth while he slept that burned the house down) or no arrests were made because, as according to the Chief Spokesman Bob Dambacher, "Would this person have died at that particular time and that particular place if riots had not occurred?" Was the criteria for his office. Also because some of them were by police/self-defense, were accidents or because the crimes were unsolved (22 - 23+ cases still remain unsolved to this day). Or at least I couldn’t find any articles naming the suspects for many of them.

Some really interesting cases here, thanks for posting them.

No problem. I’ve put a ton of research into this and with crime in general for many years.