The FBI regularly chronicles active shooter incidents. Because there is no set definition of a mass shooting, the data can appear different depending on the source. In this gallery, we included shootings that took place primarily in public and in which the victims were overwhelmingly not related to the perpetrator.
Some of the shooters began their rampages at home and then moved into the public places. Some shooters moved from place to place, killing people along the way, and others killed all of their victims in one particular location.
These are the deadliest mass shootings in American history.
Pinelake nursing home, 2009 (8 dead)
In 2009, Robert Stewart entered a nursing home in Carthage, North Carolina and shot 11 people. Eight died and three were wounded. Stewart was shot by a police officer at the scene and was ultimately sentenced to over 100 years in prison.
Craig, Alaska fishing boat, 1982 (8 dead)
This case remains unsolved more than three decades later.
In 1982, Mark Coulthurst, his pregnant wife, Irene, their two young children and a group of teenage deckhands were all shot to death and burned with their fishing boat in the waters off of Craig, a tiny Alaskan village.
Howard Johnson's New Orleans, 1973 (8 dead)
In 1973, Mark Essex, 23, shot eight people to death and wounded at least 10 more at the Howard Johnson's hotel in downtown New Orleans. The dead included patrons, employees and several police officers.
Goleta, California postal facility, 2006 (7 dead, plus the shooter)
Jennifer San Marco, a former U.S. Postal Service employee, entered the Goleta mail sorting facility in January 2006 and shot seven employees to death before taking her own life.
Miami welding shop, 1982 (8 dead)
On August 20, 1982, middle school teacher Carl Brown took a 12-gauge shotgun into Bob Moore's welding shop in Miami. Brown killed eight people and wounded three. He fled the scene but was later killed by witnesses in a car.
Wedgwood Baptist Church, 1999 (8 dead, plus gunman)
In 1999, teens were gathered at the Wedgwood Baptist Church in Forth Worth, Texas for a prayer rally when Larry Gene Ashbrook entered with two handguns. Along with the eight dead, seven people were injured. Ashbrook then shot and killed himself.
Manchester, Connecticut beer distribution center, 2010 (8 dead, plus gunman)
In August 2010, Omar Sheriff Thornton killed eight workers at the Hartford Distributors beer facility where he'd just been fired for theft. Thornton pulled two pistols from his lunchbox. Two others were injured before he turned the gun on himself.
Westroads Mall in Omaha, Nebraska, 2007 (8 dead, plus gunman)
After stealing a semi-automatic rifle from a relative, Robert A. Hawkins, 19, killed eight people and wounded two more before killing himself.
San Francisco office building, 1993 (8 dead, plus gunman)
In 1993, Gian Luigi Ferri walked into a San Francisco office with pistols modified to fire at the rate of fully automatic weapons. Along with the dead, Ferri also wounded six more people before committing suicide.
Kentucky printing office, 1989 (8 dead, plus gunman)
On a September morning in 1989, Joseph Thomas Wesbecker, a former employee, entered the office of Standard Gravure in Louisville. The 30-minute killing spree concluded when Wesbecker shot himself. Along with the dead, 12 people were injured.
Dayton, Ohio bar, 2019 (9 dead, plus gunman)
Nine people, including the shooter's 22-year-old sister, were shot and killed less than 14 hours after another mass shooting at an El Paso, Texas mall. Police shot and killed the shooter approximately 60 seconds after the massacre began.
Alaska mining town, 1984 (9 dead, plus gunman)
A drifter named Michael Silka is believed to have killed a neighbor before shooting several more people to death in 1984 in Manley Hot Springs, a remote town in central Alaska. The spree concluded with a shootout between Silka and police in which Silka and and a state trooper were killed.
Emanuel African American Methodist Church, 2015 (9 dead)
In 2015, 21-year-old white supremacist Dylann Roof shot and killed nine congregants at this historically black church in Charleston, and injured one other person. Roof was convicted of 33 federal hate crime and murder charges and was sentenced to death.
Umpqua Community College, 2015 (9 dead, plus gunman)
Student Chris Harper-Mercer opened fire on a college class in Oregon, killing nine and wounding eight more. Harper-Mercer then killed himself after exchanging fire with police.
Portland Trail Blazers players are seen here observing a moment of silence for the Umpqua Community College shooting victims in 2015.
Red Lake Indian Reservation, 2005 (9 dead, plus gunman)
Jeffrey Weise, 16, started his killing spree at home and continued to Red Lake Senior High School in Minnesota. Weise shot students, a teacher and, finally, himself. In addition to the nine people he killed, Weise also wounded five people.
Atlanta office building, 1999 (9 dead, plus gunman)
Mark O. Barton shot nine employees in two Atlanta office buildings in 1999, before ultimately killing himself. Hours later, police discovered that he had beaten three members of his family to death, possibly days earlier.
Virginia Beach Municipal Center (12 dead, plus gunman)
On May 31, 2019, 11 city employees and one private contractor were shot to death in the Virginia Beach Municipal Center Operations building.
The shooter, identified as engineer DeWayne Craddock, had worked for the city for 15 years before quitting for "personal reasons." Craddock died in an ensuing gun battle with police.
Pittsburgh synagogue, 2018 (11 dead)
Eleven people were shot dead in the Tree of Life synagogue in Pittsburgh's Squirrel Hill neighborhood on October 28, 2018. The suspect, 46-year-old Robert Bowers, reportedly posted anti-Semitic messages online before the shooting.
Aurora, Colorado theater, 2012 (12 dead)
On July 20, 2012, James Holmes (seen here) opened fire in a midnight screening of "The Dark Knight Rises" at a theater in Aurora. Twelve people died and 70 more were injured.
Jacksonville, Florida, 1990 (13 dead, plus gunman)
James Edward Pough killed 13 people and wounded six others in a string of attacks at multiple locations over two days in Jacksonville in 1990. Then he killed himself.
Washington Navy Yard, 2013 (12 dead, plus gunman)
On September 16, 2013, former contractor Aaron Alexis, 34, opened fire with a Remington 870 shotgun inside the Washington Navy Yard, killing 12 and wounding eight before dying in a shootout with police.
Thousand Oaks bar shooting, 2018 (12 dead, plus gunman)
On Nov. 7, 2018, Marine veteran Ian David Long, 28, walked into the Borderline Bar & Grill in Thousand Oaks, California and opened fire. Eleven patrons were killed, and a police officer responding to the shooting also died in the attack. Sgt. Ron Helus was shot five times by the gunman before being killed by friendly fire. Long is believed to have killed himself. Along with the dead, at least 18 people were injured, according to reports.
Camden, New Jersey, 1949 (13 dead)
In one of the first modern mass shooting incidents in U.S. history, 28-year-old war veteran Howard Unruh shot 13 people to death in his neighborhood in 1949. Unruh was eventually captured and spent the rest of his life in a mental hospital, dying in 2009.
Seattle gambling hall, 1983 (13 dead)
Benjamin Ng (seen here) was one of three gunmen who opened fire at the Mah Mee gambling club in Seattle's Chinatown in February 1983. The gunmen killed 12 men and one woman. All three suspects escaped at the time, but were later captured, tried and convicted.
Fort Hood, Texas, 2009 (13 dead)
On November 5, 2009, army psychiatrist Maj. Nidal Malik Hasan killed 13 soldiers and civilians and wounded 32 others at an army base in Texas. Hasan was eventually sentenced to death.
Binghamton, New York immigration center, 2009 (13 dead, plus gunman)
On April 3, 2009, Jiverly Wong, 41, entered the American Civic Association community center, where immigrants were taking a citizenship exam, and opened fire. Wong killed 13 people before taking his own life.
San Bernardino, California, 2015 (14 dead, plus the 2 shooters)
On December 2, 2015, Syed Farook and wife Tashfeen Malik opened fire on a holiday lunch at the Inland Regional Center in San Bernardino. They killed 14 people and wounded more than a dozen others in a terrorist attack inspired by ISIS. The couple died in a shootout with police.
University of Texas, Austin, 1966 (16 dead, plus gunman)
In 1966, Marine-trained sniper Charles J. Whitman shot at passersby from the University of Texas clock tower. Whitman killed 16 people (a 17th victim from the shooting died in 2001 due to injuries) and injured more than 30. Whitman was finally shot and killed by a police officer.
Edmond, Oklahoma post office, 1986 (14 dead, plus gunman)
On August 20, 1986, mail carrier Pat Sherrill walked into a post office in Edmond and killed 14 people and wounded six others before killing himself.
Columbine High School, 1999 (13 dead, plus the 2 gunmen)
On April 20, 1999, two seniors at Colorado's Columbine High School murdered 12 fellow students and one teacher. The two also wounded 26 before killing themselves.
Marjory Stoneman Douglas High School, 2018 (17 dead)
On Feb. 14, 2018, a gunman opened fire at a high school in Parkland, Florida. Seventeen people were killed and 17 more were injured. Police identified the suspect as Nikolas Cruz, 19, a former student. Cruz has been charged with 17 counts of first-degree murder.
San Ysidro, California McDonald's, 1984 (21 dead, plus gunman)
On July 18, 1984, James Oliver Huberty — armed with an Uzi semiautomatic rifle, a shotgun and a pistol — killed 21 people and injured 19 others in a McDonald's before he was shot to death by police.
El Paso, Texas mall (22 dead)
Just after 10:30 a.m. on August 3, 2019, a gunman entered a Walmart in El Paso, Texas and began shooting at shoppers with an assault weapon.
Minutes before his rampage, the alleged shooter reportedly shared a four-page racist document on the forum 8chan. Police arrested a 21-year-old white man at the scene. The alleged shooter has been charged with capital murder.
Luby's Cafeteria in Texas, 1991 (23 dead, plus gunman)
George Hennard opened fire at Luby's Cafeteria in Killeen, Texas after crashing his Ford Ranger through the front glass of the family restaurant on October 16, 1991. 23 people died and 20 more wounded. He then killed himself in a restroom.
First Baptist Church, Sutherland Springs, Texas, 2017 (26 dead, plus gunman)
Devin Patrick Kelley opened fire on Sunday services at the First Baptist Church in Sutherland Springs, Texas, on Nov. 5, 2017, killing 26 people and wounding about 20 others. Kelley killed himself after a brief police chase.
Sandy Hook Elementary School, 2012 (27 dead, plus gunman)
On the morning of December 14, 2012, Adam Lanza, 20, shot 27 people to death. The dead included 20 first graders and six women at Sandy Hook Elementary School in Newtown, Connecticut, as well as Lanza's mother. Then he took his own life.
Virginia Tech, 2007 (32 dead, plus gunman)
On April 16, 2007, Virginia Tech senior Seung-Hui Cho killed 32 people and injured 23 on the university's campus before killing himself.
Orlando, Florida nightclub shooting, 2016 (48 dead, plus gunman)
Omar Mateen entered Pulse, a popular gay nightclub, in the early morning of June 12, 2016, and started shooting. He killed 48 people and wounded 53 others. Mateen was killed by SWAT officers.
Las Vegas shooting, 2017 (58 dead, plus gunman)
On Sunday, October 1, 2017, Stephen Paddock, 64, opened fire from the 32nd floor of the Mandalay Bay Resort, killing 58 people and injuring more than 500 at the Route 91 Harvest Music Festival. Paddock had already shot himself when a SWAT team entered his hotel room.
This is the deadliest mass shooting in American history, to date.