July 2012: Heavily armed James Holmes opened fire in a movie theatre in Aurora, Colorado, killing 12 and wounding 59. He was arrested soon after from near the scene of the crime.
January 2011: A gunman opened fire at a public gathering outside a grocery in Tuscon, Arizona, killing six and wounding 12 others. Congresswoman Gabrielle Giffords was severely injured with a gunshot to the head.
November 2009: US army psychologist Major Nidal Hasan opened fire at a military base in Fort Hood, Texas, leaving 13 dead and 42 wounded.
April 2009: A man shot dead 13 people at a civic center in Binghamton, New York.
March 2009: Six people were shot dead in a high-grade apartment building in Santa Clara, California.
March 2009: A heavily-armed gunman shot dead eight people, many of them elderly and sick people, in a private-owned nursing home in North Carolina.
March 2009: A 28-year-old laid-off worker opened fire while driving a car through several towns in Alabama, killing 10 people.
December 2008: A man dressed in a Santa Claus suit opened fire at a family Christmas party in Covina, California, then set fire on the house and killed himself. Nine bodies were found in the debris of the house.
September 2008: A mentally ill man who was released from jail one month earlier shot eight people in Alger, Washington, leaving six dead and two wounded.
February 2008: A man opened fire in a lecture hall at Northern Illinois University in DeKalb, Illinois, killing five students and wounding 16 others before laying down his weapon and surrendering.
February 2008: A shooter who is still at large tied up and shot six women at a suburban clothing store in Chicago, leaving five of them dead and one injured.
December 2007: A woman and her boyfriend shot dead six members of her family on Christmas Eve in Carnation, Washington.
December 2007: A 20-year-old man killed nine people and injured five others at a shopping centre in Omaha, Nebraska.
April 2007: A student shot and killed 32 people and wounded 15 others at Virginia Tech in Blacksburg, Virginia, before shooting himself, making it the deadliest mass shooting in the US after 2000.
October 2006: A truck driver killed five schoolgirls and seriously wounded six others in a school in Nickel Mines, Pennsylvania before taking his own life.
March 2005: A man opened fire at a church service in Brookfield, Wisconsin, killing seven people.
November 2004: A hunter killed six other hunters and wounded two others after an argument in Birchwood, Wisconsin.
August 2003: A laid-off worker shot and killed six of his former workmates in Chicago.
September 1999: A gunman opened fire at a prayer service in Fort Worth, Texas, killing six people before committing suicide.
October 2002: A series of sniper-style shootings left 10 dead in Washington DC.
April 1999: Two teenage schoolboys shot and killed 12 schoolmates and a teacher at Columbine High School in Littleton, Colorado, before killing themselves.
July 1999: A stock exchange trader in Atlanta, Georgia, killed 12 people, including his wife and two children, before taking his own life.