Those that have grabbed the most headlines have been those in which the victims appear truly random — the shooting at a Sikh temple in Wisconsin earlier this month, for example, or the shooting in an Aurora, Colorado, movie theater in July.
Some of the highest-profile acts of gun violence included:
Shooting at Auburn University in Alabama - June 10
Desmonte Leonard, the 22-year-old suspected shooter, turned himself in to police several days after three people were killed and another three wounded in a shooting at a party near Auburn University.
Bar shooting in Tuscaloosa, Alabama - July 17
At least 17 were wounded after a gunman opened fire with an assault rifle at the Copper Top bar, Reuters reported. The motive for the attack was unclear.
Movie theater massacre in Colorado - July 20
Authorities identified James Holmes, 24, as the alleged gunman responsible for killing at least 12 people and injuring dozens during a mass shooting inside a crowded movie theater in Aurora, Colorado, during a midnight screening of the new Batman movie.
Sikh temple shooting in Wisconsin - Aug. 5
Wade Michael Page, an Army veteran who has been linked to white supremacy groups, shot temple goers and a police officer during evening services at the temple before killing himself. A total of six people died in the incident.
Shooting at Texas A&M University - Aug. 13
Three, including the gunman, were killed after a shooting near the Texas A&M University campus. The motive for the attack was unknown.
Family Research Council shooting in Washington - Aug. 15
Floyd Corkins, 28, was indicted on one federal and two District of Columbia charges after being arrested for walking into the FRC lobby with a handgun, a box of ammunition and 15 Chick-fil-A sandwiches and opening fire.
Shooting near the Empire State Building, New York City - Aug. 24
A shooting near New York City's Empire State building left two dead, including the suspected gunman, and eight injured, according to early reports. The New York Post described the gunman as "a disgruntled worker" who "stalked a colleague down a Midtown street, shot him dead and then turned his weapon on random pedestrians outside the Empire State Building."