The couple, a 28-year-old man and a 30-year-old woman, appeared to have fallen about 30 meters along the ice-covered cliff tracks on Dorr Mountain, the NPS said.
Their bodies were recovered by Park Service guards with the help of Mount Desert Island Search and Rescue and a helicopter from the Main Forest Service, according to the NPS. NPS guards and the Maine State Police are investigating, with the help of the Bar Harbor Police Department.
The two hikers arrived in Bar Harbor, Maine, on Tuesday and were last heard on Thursday around noon. The woman had discussed her interest in climbing Cadillac Mountain during a call with relatives, the NPS said.
The NPS said concerns about the whereabouts increased on Friday afternoon, when the couple did not check out of the hotel as scheduled or did not return to the vehicle. The search began on Friday night, after family members reported that the couple was late to check-in.
The night search involved a Coast Guard helicopter equipped with thermal imaging, which unsuccessfully searched for heat signatures near the Dorr and Cadillac mountains, the NPS said. Researchers on foot discovered the bodies on Saturday morning, officials said.