In the early months of 2023, the United States has gotten no reprieve from its epidemic of mass shootings.

Some happen in public places, bringing terror to the spaces Americans pass through every day, while others happen behind the closed doors of a home. Some are motivated by personal grievances, while others are terrifyingly random. Some capture widespread attention, while others are barely noticed outside the local area.

There is no consensus on what constitutes a mass shooting; different groups define it differently, depending on circumstances including the number of victims, whether the victims are killed or wounded, and whether the shooting occurs in a public place. The Gun Violence Archive, a nonprofit research group that tracks gun violence using police reports, news coverage and other public sources, defines a mass shooting as one in which at least four people were killed or injured.

As of mid-April, the Gun Violence Archive has counted at least 145 mass shootings in the United States this year.

Last year, the group counted 647 mass shootings. Of those, 21 involved five or more fatalities.

Here is a small slice of the year’s mass shootings.

April 10: Louisville, Ky.

At least five people were killed and six others were injured in a shooting at a bank in downtown Louisville, Ky., the police said.

March 27: Nashville

A heavily armed assailant shot and killed three children and three adults at a private Christian elementary school. The shooter, who the authorities said was a former student at the school, was shot and killed by the police.

Feb. 19: Memphis

Eleven people were shot, one fatally, at two separate crime scenes that the authorities said they believed were connected.

Investigators said they had identified three people of interest who they believed could be involved in the shootings. Their names were not made public.

Feb. 17: Tate County, Miss.

A 52-year-old man went on a shooting rampage at multiple locations in rural Mississippi, killing six people, including his ex-wife and two siblings who were both in their 70s, the authorities said.

The gunman, who was taken into custody, began his killing spree at a convenience store in his hometown, Arkabutla, Miss., where he fatally shot a man who appeared to have no connection to him, the police said. Arkabutla is an unincorporated community about 45 miles south of Memphis.

Feb. 13: East Lansing, Mich.

Three students were killed and five others were wounded in shootings at two buildings on the Michigan State University campus.

The gunman, a 43-year-old man who had no known connection to the university, died of a self-inflicted gunshot wound, the police said.

Feb. 1: Washington, D.C.

A gunman attacked people on a bus and inside a Metro station in Southeast Washington before bystanders tackled him and officers took him into custody. A transit employee who tried to intervene was killed, and three other people were injured.

Jan. 28: Los Angeles

Three people were killed and four others wounded in an early-morning shooting in an upscale neighborhood near Beverly Hills, Calif. The Los Angeles Police Department said the shooting took place at a short-term rental.

Jan. 23: Half Moon Bay, Calif.

Seven people were fatally shot and one was transported to a hospital with life-threatening injuries after a gunman opened fire at two separate farms. A 67-year-old man who lived and worked at one of the farms, and previously worked at the other, was arrested; the authorities believe he intentionally targeted his victims.

Jan. 21: Monterey Park, Calif.

A 72-year-old gunman killed 11 people and wounded at least nine others at a dance hall in a predominantly Asian American community as they celebrated the Lunar New Year. The police were investigating the motives of the gunman, who the police said was found dead a day later from a self-inflicted gunshot wound.

Jan. 16: Goshen, Calif.

Four generations of a single family were fatally shot by two intruders inside a home in California’s San Joaquin Valley. The dead included a 72-year-old woman who was asleep in bed; a teenage mother and her infant; and a 19-year-old man.

Although some members of the family had been involved in gangs, the police said, the nature of the attack appeared to be a calling card of Mexican drug cartels.

Jan. 4: Enoch, Utah

Eight people, all in the same family, were killed inside a home in what the police said was a murder-suicide. The victims included five children, ranging in age from 4 to 17.