The list of U.S. mass shootings continues to grow.

The mass shooting that left at least 10 people dead in Monterey Park, Calif., on Saturday night is the deadliest in the United States since the massacre in Uvalde, Texas, last May, when nineteen children and two teachers were killed.

Saturday’s shooting is also the second major attack in less than a week in California. Last Monday, gunmen killed six people in Tulare County, Calif., including a 16-year-old mother and her 10-month-old child, in a shooting that the police said was likely gang related.

There is no consensus on what constitutes a mass shooting, complicating the efforts of government, nonprofits and news organizations to document the scope of the problem. The Gun Violence Archive, a nonprofit research group, defines a mass shooting as involving at least four people killed or injured.

By that measure, there have been 33 mass shootings so far in 2023, according to the group. It counted 648 mass shootings in 2022, 21 of which involved five or more fatalities.

Here is a partial list of recent mass shootings in the United States:

Nov. 22: Chesapeake, Va.

A Walmart employee opened fire in a break room as the store was preparing to close for the night, killing six people, the authorities said. The gunman was found dead, apparently from a self-inflicted gunshot wound, according to the police.

Nov. 20: Colorado Springs

Five people were killed and 17 injured by gunfire in a shooting at an L.G.B.T.Q. nightclub. The gunman was injured and taken to a hospital.

Nov. 13: Charlottesville, Va.

Three University of Virginia students, all members of the football team, were killed and two were wounded when a gunman, a former player, opened fire in a garage after a field trip to see a play in Washington.

Oct. 13: Raleigh, N.C.

A gunman, described by the authorities only as a “white male juvenile,” killed five people, including an off-duty police officer, and wounded two others. The attacks drew a large response from law enforcement agencies to the residential area near the Neuse River Greenway, a popular bike trail for Raleigh residents.

Sept. 7: Memphis, Tenn.

Memphis was effectively closed down during an hourslong manhunt for a 19-year-old gunman who killed four people while streaming some of the violence on Facebook Live. The violence involved several shootings and carjackings over the course of the day.

July 4: Highland Park, Ill.

Seven people were killed and dozens more wounded when a gunman opened fire from the roof of a building in Highland Park, a suburb north of Chicago, during a Fourth of July parade. The 21-year-old was taken into custody several hours later.