In late October, a 4-year-old boy in Amite City, Louisiana, went through his mother’s purse, found her legally owned .22-caliber pistol, and put it in his backpack. He took the loaded gun to his pre-kindergarten class, where he showed it to a girl he liked, who then told a teacher. A month earlier, in Chico, California, a nearly-identical incident took place: A teacher at Chapman Elementary School discovered a .22-caliber revolver in the backpack of a 5-year-old. The boy said that he found the firearm at home. He thought it was a toy.

While the boys did not bring weapons to school with intent to harm their peers, they represent some of the youngest offenders in a trend fueled by the ubiquity of firearms in the United States. Since the start of the school year roughly three months ago, students from kindergarten through high school have been caught bringing guns onto campus at least 77 times, according to a survey of media reports. Excluding weekends, that works out to once every 29 hours. Firearms are entering school property through the knapsacks, jackets, and cars of students in cities, suburbs, and rural towns across America, as the map below shows:

Florida had the most incidents, with nine. The five Gulf Coast states alone — Florida, plus Texas, Louisiana, Alabama, and Mississippi — account for nearly a quarter of reported incidents. It’s a corner of the country where gun ownership is surging, even as the share of Americans who live in a household with at least one gun (32 percent, according to a June study in Injury Prevention) is lower than it’s ever been. Three Gulf Coast states — Louisiana, Mississippi, and Alabama — have gun ownership rates 10 to 16 percent higher than the national average, along with the highest gun-death rates in the nation.

Kids bring guns to school for a number of reasons. A 15-year-old in Georgetown, Texas, was placed in juvenile detention after a trainer discovered a group of boys in a high school locker room taking pictures with a stolen 9mm handgun. On the South Side of Chicago, a 12-year-old brought a gun to his elementary school because was being bullied by a classmate. A 15-year-old high school student in Fort Walton Beach, Florida, took a loaded Ruger revolver to school to kill himself. One Mississippi high school student brought a .38 special revolver in his backpack “in case there was a shooting at school,” a police official said.

Some states have laws designed to hold adults accountable when a child brings a gun to school, but they are rarely enforced, even when there are deadly consequences. Often times, it is the child who is led away in handcuffs: In Middletown, Ohio, in September, a 9-year-old student was taken into custody after a teacher found a loaded handgun in his locker. Since the start of the school year, at least two 11-year-old boys and four 12-year-old boys have been detained. Some punishments go even further: An eighth-grade boy who hid a gun in the ceiling tiles of his Saginaw, Michigan, middle school was held without bond.

The mother of that student was one of the few adults punished for failing to prevent a child from accessing a firearm. (In total, adults were charged in just five cases since the school year began.) The Michigan Department of Human Services successfully petitioned to strip her of custody of her four children. In interviews with local press, family members said the juvenile was a victim of bullying at school. “He was dealing with a lot,” said an aunt.

“That’s the way these kids are handling things right now,” said the boy’s cousin. “They get bullied and nothing gets done and then they bring guns to school.”