LINCOLN — Fifty years ago, when Betty and Barney Hill of Portsmouth drove through northern New Hampshire after a trip to Canada, they had no idea their journey would become the stuff of legends.

Now the Hills are the subject of a historical marker on Route 3 in Lincoln.

“On the night of September 19-20, 1961, Portsmouth, N.H. couple Betty and Barney Hill experienced a close encounter with an unidentified flying object and two hours of ‘lost’ time while driving south on Rte. 3 near Lincoln,” reads the historical marker. “They filled an official Air Force Project Blue Book report of a brightly lit cigar-shaped craft the next day, but were not public with their story until it was leaked in the Boston Traveler in 1965. This was the first widely reported UFO abduction report in the United States.”

The marker is in front of Cabin 20 at the Indian Head Resort in Lincoln, across the street from the granite stone face called Indian Head.

The Hills said they didn’t realize what had happened that night until they went under hypnosis and told the story of being abducted by aliens, taken aboard their craft, questioned and given a physical examination.

Several years ago, Mike Stevens of Farmington circulated a petition to request a marker to commemorate the Hills’ UFO experience. The Hills’ niece, Kathleen Marden, said she worked with the state Department of Cultural Resources for several years to make the marker a reality.

“Every statement had to be footnoted and supported by ample evidence that it was true and accurate,” she said.

Barney Hill died in 1969, Betty Hill in 2004.

Franconia resident Jayne O’Connor said she lived in Portsmouth in the early 1980s, a couple doors down from Betty Hill, who wrote several books after her experience.

“She was a quirky little lady,” O’Connor said Tuesday, “and a lot of fun to know.”

O’Connor said that Betty would come up to the Indian Head Resort during its annual psychic weekend, bringing a sculpture resembling the alien she said she and her husband encountered all those years ago.

Indian Head Resort is not letting the 50th anniversary go unnoticed. The resort is holding an event Sept. 23-25, hosted by Marden. Among other activities, there will be a guided tour of the route the Hills took that starry night in 1961.

“That’s exactly the kind of thing Betty would have loved to come up for,” said O’Connor, who is also president of the White Mountains Attractions Association. “She really enjoyed talking about her experience.”