Marie-Hélène Gauvin, 17, Tommy Losier, 18, Brian Basque, 19, and Alexandre McGraw, 20, were in the car that plunged off a slippery back road in Tracadie-Sheila early Saturday morning.
Their bodies were recovered from the frigid and murky Tracadie River later that afternoon.
The three young men were from communities in the Tracadie-Sheila area, while Gauvin was from Pointe-Canot.
Their deaths are being felt far and wide across the region.
"It's not only the Tracadie-Sheila, the town that's affected," said Mayor Aldeoda Losier. "People feel bad at this time of the year, when Christmas is at the door, having to go through this event."
Churchgoers in Tracadie-Sheila observed a moment of silence for the victims on Sunday.
Many residents responded to a Facebook campaign to turn off their Christmas lights to mark the loss.
Basque had turned 19 on Friday. His mother gave him a car, and he went out with his friends to celebrate, his uncle, Jean-Claude Doiron, told CBC News.
Officials said Basque was driving the car. It's unclear what happened, but sometime early Saturday the car slipped off the narrow dirt road and plunged into the Tracadie River far below.
Mayor Losier said it happened on a former military range that is usually inaccessible at this time of year because of snow.
“What we heard is during the evening when they went out there was no ice on the road. But when they came back, there was some ice on the road,” he said Sunday.
RCMP said it would be at least a week before they have more information about the cause of the crash or contributing factors.
Investigators are waiting for toxicology reports from the autopsies and a report from an accident reconstruction specialist.
The car is being inspected to determine whether there were any mechanical problems.