http://www.canada.com/news/Mass+shootings+since+1999/1461956/story.html— Littleton, Colorado, April 1999. Two teenage boys shoot and kill 12 students and a teacher at Columbine High School before killing themselves.
— Atlanta, Georgia, July 1999. A stockmarket day trader goes on a day-long shooting rampage, killing 12 people including his wife and two children before taking his own life.
— Fort Worth, Texas, September 1999. A gunman opens fire at a prayer service, killing six people before committing suicide.
— Washington, October 2002. A series of sniper-style shootings, some carried out from the boot of a car, claims 10 lives, mostly in the Washington area. Many of the attacks were carried out with a semi-automatic assault rifle.
— Chicago, August 2003. A worker who was laid off shoots and kills six of his former co-workers with a semi-automatic pistol. The shooter had a lengthy arrest record, including for weapons offenses.
— Birchwood, Wisconsin, November 2004. A hunter opens fire with an SKS assault rifle, killing six other hunters and wounding two after an argument.
— Brookfield, Wisconsin, March 2005. A man fires 22 rounds during a church service, killing seven people.
— Nickel Mines, Pennsylvania, October 2006. A truck driver armed with two rifles, a semi-automatic handgun and 600 rounds of ammunition kills five schoolgirls execution-style in an Amish schoolhouse, and seriously wounds six others before shooting himself.
— Blacksburg, Virginia, April 2007. A student shoots 47 people at Virginia Tech, killing 32 before he commits suicide, in the deadliest mass shooting in the United States.
— Omaha, Nebraska, December 2007. Nine people are killed and five others injured after a 20-year-old shooter armed with a military-style assault rifle attacks shoppers in a mall.
— Carnation, Washington. December 2007. A woman and her boyfriend shoot dead six members of her family, including two children, ages three and six, on Christmas Eve, using large-caliber pistols.
— Chicago. February 2008. Six women are tied-up and shot at a suburban clothing store. Five of the women die. The gunman has not been found.
— DeKalb, Illinois. February 2008. A man opens fire in a lecture hall at Northern Illinois University, killing five students and wounding 16 before turning his weapon on himself.
— Alger, Washington. September 2008. A mentally ill man who had been released from jail a month earlier shoots eight people, killing six.
— Covina, California. December 2008. A man dressed in a Santa Claus suit opens fire at a family Christmas party at his ex-wife's home and then sets fire to the house. Nine people are killed in the home. The gunman later kills himself.
— Geneva County and Coffee County, Alabama. March 12 2009. In a shooting spree that tears through several towns, a 28-year-old out-of-work man kills 10 people, including his mother and a toddler.
— North Carolina. March 29, 2009. A heavily-armed gunman shoots dead eight people, many elderly and sick patients, in a North Carolina nursing home.
— Santa Clara, California, March 30, 2009. Six people are shot dead in an apparent murder-suicide at a home in an upscale Silicon Valley neighborhood.
— Binghamton, New York. April 3, 2009. Up to 13 people are killed as a gunman goes on a rampage at a civic center in the town of Binghamton.