Power was restored across midtown Manhattan and the Upper West Side just before midnight after a massive blackout left 73,000 customers without electricity for hours on Saturday evening, Con Edison said.
The last of the six power grid networks that were down had been restored by just before midnight, Con Edison said.
The blackout stopped subway service, halted Broadway shows and a concert by Jennifer Lopez at Madison Square Garden, disabled traffic lights and trapped people in elevators. Carnegie Hall was evacuated mid-show and the singers continued their performance outside.
No injuries or fatalities were reported.
There was nothing to suggest anything deliberate, according to a senior fire official and a senior NYPD official who spoke on a condition of anonymity.
The outage stretched from about 34th Street to 72nd Street and from the far west side to Fifth Avenue, according to the Con Ed power outage map. It included Rockefeller Center.
Firefighters responded to a transformer fire on 64th Street and West End Avenue, the FDNY tweeted. Firefighters were also responding to reports of people trapped in elevators.
There was limited subway service across New York City, according to the MTA. That included a partial suspension of the 1, 2, 3, 4, 5, 6, 7, A, C, E, D, F, M, L, M, Q, R and S, lines.
At least four subway stations were blackened, the MTA says. Train operators were able to manually change the signals and bring at least one car or door to a subway station, so no one had to get out on the tracks.
Some people were trapped in subway elevators, but they were rescued, the MTA said.
Several people in the Columbus Circle subway station tweeted photos and videos of the darkened platform.
Traffic lights were out and police were directing traffic around Rockefeller Center. In other areas, civilians stepped in to direct traffic, according to photos and videos posted to social media.
All but three Broadway shows were blackened. "Pretty Woman" and "Cher," had audiences standing on the streets. The casts of "Come From Away" and "Hadestown" gave impromptu performances to the crowd on the street.
The signs at Radio City Music Hall and on the entrances to Rockefeller Center were blackened.
Some businesses closed and put up signs in their windows. Other restaurants continued serving and pouring pints in the pitch black.
In a statement, Gov. Cuomo called the incident "unacceptable" and said he directed the State Police, MTA and Public Service Commission to deploy personnel and resources to restore the power as soon as possible.
"We are in constant communication with Con Ed, who has an effort underway to begin restoration of power by midnight tonight," Cuomo said.
Cuomo also said he was directing the Department of Public Service to investigate the exact cause of the massive outage to "prevent an incident of this magnitude form happening again."
Cuomo was heading to the Con Edison command center on the west side, sources told NBC 4 New York.
Mayor de Blasio, who was in Iowa on Saturday, cancelled campaign events and planned to come back to the city on Sunday, according to City Hall. After the power had returned, De Blasio also tweeted that he'd directed the city's agencies to look into the incident.
The outage comes on the anniversary of the 1977 New York City outage that left most of the city without power. That outage was caused by a lightning strike and took 25 hours to restore.
In a tweet announcing the power restoration, Cuomo said that people "should continue to exercise caution as everything returns to normal." He also commended the public's response to the blackout.
"When things are at their worst, New Yorkers are at their best, and they were at their best tonight," Cuomo said.