The 66-year-old resident was working on her computer inside the East River high-rise when the hobby craft smashed through the window at around 5:45 p.m., according to the sources.

The 1-by-1-foot device — which has a 10-inch propeller and a camera — landed on the floor just 4 feet away from her, cops said.

“Poor lady. She’s lucky she wasn’t killed,” said Stephanie Bowden, 23, who was visiting her boyfriend’s apartment 11 floors below at the time.

Police on Sunday were investigating who owns the drone, a remote-controlled 2.2-pound GoPro Karma Quadcopter model, and where it came from.

The Federal Aviation Administration also plans to look into it, police sources said.

If the owner registered the device with the FAA — which is legally required for recreational drones between .55 and 55 pounds — it can be traced back to the owner, sources said.

Police also may be able to use a serial number located on the base and battery of the drone to track down who it belongs to, sources said.

Flying drones recreationally is banned in Manhattan and nearly everywhere else in the city, except in five outer-borough parks, according to the Parks Department.

Drones are forbidden fewer than five miles from JFK or LaGuardia airports in any direction under federal aviation law. The FAA offers other “guidelines,” too, noting that the gadgets should not be flown near buildings and bridges or more than 400 feet in the air.

The 66-year-old victim of Saturday’s bizarre accident declined comment to The Post — but stunned neighbors at her building at 20 Waterside Plaza said it takes home intrusion to new heights.

Nick Ward, 24, a project engineer who lives on 30th floor, said, “That’s pretty crazy. I’d say the statistics for this happening are really, really low.”

Bowden added, “The last thing you expect is for something to come crashing through the window.

“I can’t imagine how scary that must have been.’’

Drones have caused other problems in the Big Apple.

Last year, a 28-year-old video maker was arrested for accidentally flying a drone into the Empire State Building.

In July, a 52-year-old man also was busted flying the gadget 20 feet below a passenger jet as it was landing at JFK Airport.

And in May 2015, a graffiti “artist” used a drone to spray-paint a six-story Calvin Klein billboard in Soho.

A rep for GoPro didn’t return a request for comment Sunday.