The single-engine Cessna came down on the golf course's fairway at about 8 a.m. and may have clipped trees, according to Eastside Fire and King County sheriff's officials.
Witness Kevin Adcox said the pilot hit at least two trees.
"I turned around to see and it's like, 'Wow! He sounds low,' " Adcox said. "He whacked the first tree, and I just dove and watched the rest of it two fairways down. He hit the ground once then hit a big tree and it destroyed it."
The person killed in the crash was the sole occupant of the aircraft.
The plane had reportedly just taken off from the Fall City Airport in a dense fog. Steven Griboski, who also witnessed the crash, says right after takeoff, the plane dropped to about 10 feet off the ground, hit one tree, then another.
"Then it went into a spin and then it hit the main tree which was a spruce and got it pretty good," he said.
The FAA is responding to the scene to launch an investigation. The victim's name has not been released.