On March 16, an 11-year-old child in Queens, New York, found a loaded .380-caliber handgun under his grandfather’s bed and brought it to his elementary school. The following day, another Queens boy was arrested after brandishing a loaded .38-caliber revolver in a high school stairwell. The next week in neighboring Brooklyn, a middle school student was arrested after administrators found an unloaded 9mm handgun and two magazines in his backpack.

The three incidents were among the latest examples of a trend steadily playing out across the country: With three quarters of the academic year complete — from late August, when many districts started classes, to March 15, when many concluded the third report card period — there were at least 185 incidents in which elementary, middle, and high school students were caught with guns on school grounds. That figure, culled from news databases, is an update to The Trace’s reporting in January, which found 135 such incidents in the first five months of the school year.

(Because the recent incidents in New York took place after the March 15 cutoff, they will be included in our year-end wrap-up in June.)

Research shows that America’s 55 million school children pack heat at a surprising rate. A 2011 study by the Centers for Disease Control and Prevention (CDC) found that 5.4 percent of schoolchildren carried a gun, knife, or club on school property on at least one day during the month before they were surveyed.

What motivates children to bring guns to school varies. So far this year, according to an examination of local media reports, at least four students brought guns to school in anticipation of a fight. Others brought guns to show them off, or sell them to classmates. When a 16-year-old boy was asked why he brought a loaded handgun into his Nashville, Tennessee, high school on March 10, he said, “I was just being stupid.”

Sometimes, of course, students bring guns into their schools to kill. On February 12, a 15-year-old high school student shot and killed her girlfriend and then herself at their high school in Glendale, Arizona. She got the handgun from a classmate, who stole it from his parents. On February 29, 14-year-old James Austin Hancock opened fire in the cafeteria of his junior high school in Middletown, Ohio, wounding two students. He told police that he lifted the .380-caliber semiautomatic handgun from a family member.

The ubiquity of firearms in America (civilians own an estimated 270 to 330 million) means that more kids are encountering them in the home. According to a 2014 Pew survey, a third of Americans with children under 18 at home keep a gun on the premises. There is no federal law requiring that guns be safely stored in the home, but 11 states and a number of municipalities have passed their own laws. A total of 28 states have enacted child access prevention statutes that impose criminal liability on adults who don’t secure their guns. Massachusetts is the only state that requires firearms be locked up at all times.

A few days after the shooting in Middletown, Ohio, school superintendent Curtis Philpot issued a plea to parents in his community. “If you have a firearm in your house, lock them up,” he said. “Lock them up. That’s all I ask. You’ve got one backpack. I got 1,600.”