The partial skull and teeth were found Saturday in the White Mountain National Forest near North Conway, the New Hampshire Union Leader in Manchester reported Monday.
DNA testing is being conducted on the remains. The condition of the remains could help determine when the person died, said State Police Capt. David G. Parenteau.
Parenteau said a Massachusetts family called Monday to provide information on a missing relative last seen in Portland, Maine.
Authorities hope to determine if the remains are those of a man reported missing seven years ago.
The discovery is believed to be unrelated to the disappearance of 15-year-old Abigail Hernandez of Conway, who was last seen Oct. 9 walking home from school.
Her sister, Sarah Hernandez, issued a public plea Monday for information.
"If you know where Abby is, please keep her safe, and let her come back to us," she said during an evening media briefing.
Senior Associate Attorney General Jane Young said investigators were using social media extensively in hopes the girl would see messages asking her to come home.
The incident is still being investigated as a missing person case, Young said. While "that could change," she said "there is no evidence to support any criminal activity."
Investigators say they have received more than 300 tips.