Howard Barton Unruh was an American mass murderer (sometimes classified as a spree killer) who shot and killed 13 people (including three children) during a 12-minute walk through his neighborhood on September 6, 1949, in Camden, New Jersey, when he was 28 years old. The incident became known as the "Walk of Death".

On August 1, 1966, after stabbing his mother and his wife to death the night before, Charles Whitman, a former Marine, took rifles and other weapons to the observation deck atop the Main Building tower at the University of Texas at Austin, then opened fire indiscriminately on people on the surrounding campus and streets. Over the next 96 minutes he shot and killed 13 more people (including a pregnant woman) and injured 31 others.

James Urban Ruppert, is an American murderer, who was responsible for one of the deadliest shootings inside a private residence in US history. On Easter Sunday, March 30, 1975, Ruppert murdered 11 family members in his mother's house at 635 Minor Avenue in Hamilton, Ohio in what has been referred to as the "Easter Sunday Massacre." He is serving two life sentences at the Allen Oakwood Correctional Institution in Lima, Ohio.

The 1982 Wilkes-Barre Shootings was a spree killing in the United States carried out by George Emil Banks. A former Camp Hill prison guard, Banks shot 13 people to death on September 25, 1982 in Wilkes-Barre, Pennsylvania and Jenkins Township, including seven children – five being his own – their mothers, some of their relatives, and one bystander. His attorneys argued for the insanity defense, but, following a trial before jurors from Allegheny County and presided over by Luzerne County Common Pleas judge Patrick J. Toole Jr., Banks was convicted of 12 counts of first-degree murder and sentenced to death.

The Wah Mee massacre was a multiple homicide that occurred during the night of February 18–19, 1983, in which Kwan Fai "Willie" Mak, Wai-Chiu "Tony" Ng, and Benjamin Ng (no relation) bound, robbed, and shot fourteen people in the Wah Mee gambling club at the Louisa Hotel in Chinatown-International District, Seattle. Thirteen of their victims died, but Wai Chin, a dealer at the Wah Mee, survived to testify against the three in the separate high-profile trials held in 1983 and 1985. It is the deadliest mass murder in Washington state history.

The Palm Sunday massacre was a 1984 mass-murder in Brooklyn, New York, that resulted in the deaths of ten people: two women, two teenage girls, and six children. There was one survivor, an infant girl. All of the victims were shot, with a total of 19 bullets fired from two handguns at close range, most in the head, and were found in relaxed poses sitting in couches and chairs, suggesting that they had been taken by surprise.

The San Ysidro McDonald's massacre was an act of mass murder which occurred at a McDonald's restaurant in the San Ysidro neighborhood of San Diego, California on July 18, 1984. The perpetrator, 41-year-old James Huberty, fatally shot 21 people and wounded 19 others before being killed by a police sniper approximately 77 minutes after he had first opened fire. The San Ysidro McDonald's massacre was considered the worst mass shooting in the United States (in terms of number of fatalities) until 1991, and remains the eighth deadliest mass shooting in American history

The Edmond post office shooting occurred in Edmond, Oklahoma, on August 20, 1986. During a deadly rampage that lasted less than fifteen minutes, postal worker Patrick Sherrill pursued and shot twenty co-workers, killing fourteen of them, before committing suicide. Sherrill's attack inspired the American phrase "going postal".

The Luby's shooting, also known as the Luby's massacre, was a mass shooting that took place on October 16, 1991, at a Luby's Cafeteria in Killeen, Texas. The perpetrator, George Hennard, drove his pickup truck through the front window of the restaurant. He quickly shot and killed 23 people, and wounded 27 others. He had a brief shootout with police, refused their orders to surrender, and fatally shot himself.

The Columbine High School massacre was a school shooting and bombing that occurred on April 20, 1999, at Columbine High School in Columbine, Colorado, United States. The perpetrators, twelfth grade (senior) students Eric Harris and Dylan Klebold, murdered 12 students and one teacher. Ten students were killed in the school library, where the pair subsequently committed suicide. 21 additional people were injured with gunshots and gunfire was also exchanged with the police. Another three people were injured trying to escape the school.

Mark Orrin Barton was a spree killer from Stockbridge, Georgia, who killed 12 people and injured 13 more on July 29, 1999.

A comprehensive report by USA Today tracked all mass killings from 2006 through 2017 in which the perpetrator willfully killed 4 or more people. For mass killings by firearm for instance, it found 271 incidents with a total of 1,358 victims.

The Virginia Tech shooting was a school shooting that occurred on April 16, 2007, at West Ambler Johnston Hall and Norris Hall at the Virginia Polytechnic Institute and State University, in Blacksburg, Virginia. Seung-Hui Cho, an undergraduate student at the university and a U.S. resident of South Korean origin, shot and killed 32 people and wounded 17 others with two semi-automatic pistols. Six others were injured jumping out of windows to escape Cho. As police stormed Norris Hall, Cho died by suicide by shooting himself in the head.

The Geneva County massacre occurred in southern Alabama on March 10, 2009. Ten people were killed in a shooting spree by Michael Kenneth McLendon, 28, in three small communities in two counties: Kinston, Samson and Geneva, Alabama. Five of McLendon's victims were family members, starting with his mother, and two were children. After engaging in an exchange of fire with police, McLendon committed suicide, bringing the total number of dead to eleven in the related incidents. Officials at the time said this was the worst shooting event in Alabama history.

The Binghamton shootings took place on April 3, 2009, at the American Civic Association immigration center in Binghamton, New York. At approximately 10:30 a.m. EDT, Jiverly Antares Wong (also known as Jiverly Voong), a 41-year-old naturalized American citizen from Vietnam, entered the facility and shot numerous people inside. Wong had taken English language classes there from January to March 2009 before dropping out. Wong killed thirteen people and wounded four others before committing suicide.

On November 5, 2009, a terrorist mass shooting took place at Fort Hood, near Killeen, Texas. Nidal Hasan, a U.S. Army major and psychiatrist, fatally shot 13 people and injured more than 30 others. It was the deadliest mass shooting on an American military base. Hasan was shot and as a result paralyzed from the waist down. Hasan was arraigned by a military court on July 20, 2011 and was charged with 13 counts of premeditated murder and 32 counts of attempted murder under the Uniform Code of Military Justice.

An analysis by Michael Bloomberg's gun violence prevention group, Everytown for Gun Safety, identified 110 mass shootings, defined as shootings in which at least four people were murdered with a firearm, between January 2009 and July 2014; at least 57% were related to domestic or family violence.

Some studies indicate that the rate at which public mass shootings occur has tripled since 2011.

Between 1982 and 2011, a mass shooting occurred roughly once every 200 days.

Between 2011 and 2014, that rate has accelerated greatly with at least one mass shooting occurring every 64 days in the United States.

On July 20, 2012, a mass shooting occurred inside a Century 16 movie theater in Aurora, Colorado, during a midnight screening of the film The Dark Knight Rises. Dressed in tactical clothing, James Eagan Holmes set off tear gas grenades and shot into the audience with multiple firearms. Twelve people were killed and seventy others were injured, 58 of them from gunfire.

The Sandy Hook Elementary School shooting occurred on December 14, 2012, in Newtown, Connecticut, United States, when 20-year-old Adam Lanza shot and killed 26 people, including 20 children between six and seven years old, and six adult staff members. Before driving to the school, he shot and killed his mother at their Newtown home. As first responders arrived at the school, Lanza committed suicide by shooting himself in the head.

There is no fixed definition of a mass shooting in the United States. The Investigative Assistance for Violent Crimes Act of 2012, signed into law in January 2013, defines a "mass killing" as one resulting in at least 3 victims, excluding the perpetrator.

The Washington Navy Yard shooting occurred on September 16, 2013 when 34-year-old Aaron Alexis fatally shot 12 people and injured three others in a mass shooting at the headquarters of the Naval Sea Systems Command (NAVSEA) inside the Washington Navy Yard in southeast Washington, D.C. The attack took place in the Navy Yard's Building 197; it began around 8:16 a.m. EDT and ended when Alexis was killed by police around 9:25 a.m.

Several types of guns have been used in mass shootings in the United States. A 2014 study conducted by Dr. James Fox of 142 shootings found that 88 (62%) were committed with handguns of all types; 68 (48%) with semi-automatic handguns, 20 (14%) with revolvers, 35 (25%) with semi-automatic rifles, and 19 (13%) with shotguns. High capacity magazines were used in approximately half of mass shootings. Semi-automatic rifles have been used in six of the ten deadliest mass shooting events.

In August 2015, The Washington Post reported that the United States was averaging one mass shooting per day.

On December 2, 2015, 14 people were killed and 22 others were seriously injured in an Islamic terrorist attack consisting of a mass shooting and an attempted bombing at the Inland Regional Center in San Bernardino, California. The perpetrators, Syed Rizwan Farook and Tashfeen Malik, a married couple living in the city of Redlands, targeted a San Bernardino County Department of Public Health training event and Christmas party of about 80 employees in a rented banquet room. Farook was a U.S.-born citizen of Pakistani descent, who worked as a health department employee. Malik was a Pakistani-born green card holder.

Mother Jones listed seven mass shootings, defined as indiscriminate rampages in public places resulting in four or more victims killed, in the U.S. for 2015.

In December 2015, The Washington Post reported that there had been 355 mass shootings in the United States so far that year.

On June 12, 2016, Omar Mateen, a 29-year-old security guard, killed 49 people and wounded 53 others in a mass shooting inside Pulse, a gay nightclub in Orlando, Florida, United States. Orlando Police Department officers shot and killed him after a three-hour standoff.

On the night of October 1, 2017, a shooter opened fire on a crowd of concertgoers at the Route 91 Harvest music festival on the Las Vegas Strip in Nevada. He killed 58 people and wounded 413, with the ensuing panic bringing the injury total to 869. The shooter, Stephen Paddock, a 64-year-old man from Mesquite, Nevada, fired more than 1,100 rounds of ammunition from his suite on the 32nd floor of the Mandalay Bay Hotel. Paddock was found dead in his room from a self-inflicted gunshot wound. His motive remains officially undetermined.

The Sutherland Springs church shooting occurred on November 5, 2017, when Devin Patrick Kelley of New Braunfels, Texas, fatally shot 26 people and wounded 20 others during a mass shooting at the First Baptist Church in Sutherland Springs, Texas. The attack was the deadliest mass shooting in Texas and the fifth-deadliest mass shooting in the United States.

On February 14, 2018, a gunman opened fire with a semi-automatic rifle at Marjory Stoneman Douglas High School in Parkland, Florida, killing 17 people and injuring 17 others. Witnesses identified Nikolas Cruz, a 19-year-old former student at the school, as the assailant. Cruz fled the scene on foot by blending with other students. He was arrested without incident about an hour later in nearby Coral Springs.

A school shooting occurred at Santa Fe High School in Santa Fe, Texas, United States, in the Houston metropolitan area, on May 18, 2018. Ten people – eight students and two teachers – were fatally shot, and thirteen others were wounded. The suspected shooter was taken into custody and later identified by police as Dimitrios Pagourtzis, a 17-year-old student at the school.

The Pittsburgh synagogue shooting was a mass shooting that took place on October 27, 2018, at the Tree of Life – Or L'Simcha Congregation in the Squirrel Hill neighborhood of Pittsburgh, Pennsylvania. The congregation was attacked during Shabbat morning services. The shooter killed eleven people and wounded seven (he was among the wounded). Robert Gregory Bowers, 46-years-old, was arrested at the scene and charged as the suspect with 63 federal crimes, some of which are capital crimes. He has pleaded not guilty. He separately faces 36 charges in Pennsylvania state court.

A mass shooting took place on November 7, 2018, in Thousand Oaks, California, United States, at the Borderline Bar and Grill, a country-western bar frequented by college students. Thirteen people were killed, including the perpetrator, who died of a self-inflicted gunshot wound, and a police officer who was shot multiple times, with the fatal wound accidentally being fired by another officer. Ten to twelve others were injured. Police identified the killer as 28-year-old Ian David Long, a United States Marine Corps veteran.

The Virginia Beach shooting occurred on the afternoon of May 31, 2019, when a disgruntled city employee fatally shot twelve people and wounded four others in a mass shooting at a municipal building in the Princess Anne area of Virginia Beach, Virginia, United States. He was shot dead by responding police officers.

On August 3, 2019, a mass shooting occurred at a Walmart store in El Paso, Texas, United States. A gunman shot and killed 22 people and injured 24 others. The Federal Bureau of Investigation is investigating the shooting as an act of domestic terrorism and a possible hate crime. Patrick Crusius, a 21-year-old from Allen, Texas, was arrested shortly after the shooting and charged with capital murder.