On September 17–19, 2016, a series of three constructed bombs exploded, and several unexploded devices were discovered in the New York metropolitan area followed by a subsequent shooting in Linden, New Jersey during a nationwide manhunt for the perpetrator. The bombings and additional shootout left 33 people wounded, but no fatalities were reported. Federal investigators determined these explosive devices were deliberately set and identified them as part of a terrorist act.

On the morning of September 17, a pipe bomb exploded in Seaside Park, New Jersey which was intended to detonate during a 5K charity race at the height of crowded venues. Later that day, a homemade pressure cooker bomb went off in the Chelsea neighborhood of Manhattan, New York City causing extensive injuries and significant property damage to adjacent buildings. A second pressure cooker bomb was discovered four blocks away. Late on September 18, multiple bombs were discovered at the train station in Elizabeth, New Jersey. One of these bombs detonated early the next day, destroying a police robot in the attempts for authorities to disarm it and causing additional damage.

On September 19, 2016, the sole suspect—Ahmad Khan Rahimi, of Elizabeth—was identified and captured, following a shootout with police in neighboring Linden, New Jersey, which left two officers injured from gunfire. Rahimi was not part of a terrorist group, but his actions were believed to have been influenced by the extremist Islamic ideology espoused by al-Qaeda and Islamic State. In 2017, Rahimi was convicted in U.S. federal court of eight federal crimes arising from the attack. On February 13, 2018, Rahimi was sentenced to a mandatory term of life without parole.

In the morning of September 17, 2016, in Ocean County, New Jersey, the Seaside Semper Five, a 5K run event, was expected to draw as many as 3,000 people, with many of them being veterans of the United States Armed Forces. The race was delayed after a suspicious backpack was noticed in the vicinity of the starting point.

At about 9:30 a.m., shortly before the race was supposed to start, a pipe bomb exploded in a trash can on Ocean Avenue in Seaside Park. Three "rudimentary" pipe bombs, all reportedly timed to go off during the race, were later found, with only one of the three having exploded. Fragments of the device were dispersed into the nearby street and caused a sudden, loud noise which shook buildings and homes nearby. No one was physically hurt by this bombing, however.

The race was canceled after the explosion, and the beach and boardwalk in Seaside Park were evacuated. Police officials and federal agents soon went door-to-door, asking residents about information regarding the bombs or any suspicious activity they may have seen, heard, or witnessed.

In the Chelsea neighborhood of Manhattan in New York City, on the same day as the Seaside Park bombing, a pressure cooker bomb filled with shrapnel, in the form of small bearings or metal BBs, exploded in a crowded area on West 23rd Street, between Avenue of the Americas and Seventh Avenue at 8:31 p.m. The explosion occurred in front of 133 West 23rd Street in the vicinity of a construction site, at which materials were in place for exterior renovations of the Visions at Selis Manor facility, an apartment building for the blind, at 135 West 23rd Street. Other nearby buildings included the Townhouse Inn of Chelsea, and many restaurants. The Chelsea neighborhood is primarily residential, and has an active nightlife scene.

Witnesses said that the explosion "seemed to have started inside a sidewalk dumpster" in the vicinity of Sixth Avenue, and photographs of a "twisted dumpster" in the middle of West 23rd Street went viral on Twitter. A law enforcement official speaking on condition of anonymity stated that the explosion "appeared to have come from a construction toolbox" in front of a building, and photographs of the area reportedly showed a twisted, crumpled black metal box.