Mass shooters have killed hundreds of people throughout U.S. history in realms like stores, theaters and workplaces, but it is in schools and colleges where the carnage reverberates perhaps most keenly - places filled with children of tender ages, older students aspiring to new heights and the teachers planting the seeds of knowledge, their journeys all cut short.

If a mass shooting is defined as resulting in the death of four or more people, not including the perpetrator, 169 people have died in 14 such events connected to U.S. schools and colleges - from 1999′s Columbine High School massacre to Tuesday's shooting in Texas. That's according to a database compiled by The Associated Press, USA Today and Northeastern University, and to other AP reporting:

ROBB ELEMENTARY SCHOOL, May 2022, 21 dead

An 18-year-old gunman opened fire Tuesday at an elementary school in Uvalde, Texas, killing 19 children and two adults, officials said. Law enforcement killed the attacker.

OXFORD HIGH SCHOOL, November 2021, 4 dead

A sophomore student is accused of killing four people and wounding others at his school in Oxford, Michigan, near Detroit. His trial is set for September. His parents are charged with involuntary manslaughter; authorities say they ignored warning signs.

SANTA FE HIGH SCHOOL, May 2018, 10 dead

A shooter opened fire at a Houston-area high school, killing 10 people, most of them students, authorities said. The 17-year-old suspect has been charged with murder.

MARJORY STONEMAN DOUGLAS HIGH SCHOOL, February 2018, 17 dead

An attack left 14 students and three staff members dead at the school in Parkland, Florida, and injured many others. The 20-year-old suspect was charged with murder.

UMPQUA COMMUNITY COLLEGE, October 2015, 9 dead

A man killed nine people at the school in Roseburg, Oregon, and wounded nine others, then killed himself.

MARYSVILLE-PILCHUCK HIGH SCHOOL, October 2014, 4 dead

A 15-year-old used text messages to draw several cousins and friends to his cafeteria table at Marysville-Pilchuck High School in Washington state. He fatally shot four of them before killing himself.

UNIVERSITY OF CALIFORNIA, SANTA BARBARA, May 2014, 6 dead

A 22-year-old college student frustrated over sexual rejections fatally stabbed or shot six students near the school in Isla Vista, California, and injured several others before he killed himself.

SANDY HOOK ELEMENTARY SCHOOL, December 2012, 27 dead

A 19-year-old man killed his mother at their home in Newtown, Connecticut, then went to the nearby Sandy Hook Elementary School and killed 20 first graders and six educators. He took his own life.

OIKOS UNIVERSITY, April 2012, 7 dead

A former nursing student fatally shot seven people at the small private college in East Oakland, California. He died in prison in 2019.

NORTHERN ILLINOIS UNIVERSITY, February 2008, 5 dead

A 27-year-old former student shot and killed five people and wounded more than 20 others at the school in DeKalb, Illinois, before killing himself.

VIRGINIA TECH, April 2007, 32 dead

A 23-year-old student killed 32 people on the campus in Blacksburg, Virginia, in April 2007; more than two dozen others were wounded. The gunman then killed himself.

WEST NICKEL MINES AMISH SCHOOL, October 2006, 5 dead

A 32-year-old man entered an Amish schoolhouse near Lancaster, Pennsylvania, dismissed the boys, bound the girls, and fatally shot five of them before killing himself. Five others were wounded.

RED LAKE HIGH SCHOOL, March 2005, 9 dead

A 16-year-old student killed his grandfather and the man's companion at their Minnesota home, then went to nearby Red Lake High School, where he killed five students, a teacher and a security guard before shooting himself.

COLUMBINE HIGH SCHOOL, April 1999, 13 dead

Two students killed 12 of their peers and one teacher at the school in Littleton, Colorado, and injured many others before killing themselves.