A police spokesman said: "One man, believed to be the pilot of the private aircraft, was pronounced dead at the scene. No further casualties have been reported.
"Officers have cordoned off the area and conducted a search of the area.
"Some officers remain at the scene and the Civil Aviation Authority is also at the scene, where it will carry out an investigation into the cause of the crash.
"North Yorkshire Police is not yet in a position to name the deceased."
Witnesses described an "enormous explosion" as the helicopter crashed in a crop field at Aldborough near Boroughbridge at about 1.30pm today.
Emergency services were at the scene within minutes, as well as the Yorkshire Air Ambulance.
Fire crews from Boroughbridge, Knaresborough, Harrogate and Ripon attended, it is understood, along with the police and ambulance service.
Police officers cordoned off the crash site and began to conduct a search of the area.
Witness Katie McCann, of London, who grew up in the village, said the crash took place behind Aldborough Hall.
She described what sounded like an "out of control plane or helicopter".
"Then I heard an enormous explosion," she said.
"[One man] said he had seen it. It was a red and white helicopter.
"He said it had climbed up into the cloud like it was trying to recover itself, and then dropped like a stone."