With the smash of a champagne bottle and loud cheers all around, the Gay Head Light came to rest Saturday directly above the spot where experts believe it will be safe from erosion for 150 years or more. The three-day move, which started well ahead of schedule, is the most significant milestone in the efforts to preserve and restore the historic lighthouse.

Onlookers cheer for moment of history. — Mark Lovewell

The lighthouse came to rest on its new foundation at 11:10 a.m.

Shrouded in fog, earlier in the morning the 400-ton brick and mortar lighthouse stood less than 20 feet from its destination above a large concrete pad southeast of eroding clay cliffs. As workers from Expert House Movers and International Chimney Corp. made final adjustments, a growing crowd of visitors gathered on a dirt path that ended with metal barriers near the pad.

Jeffrey Madison, who grew up in Aquinnah and now lives on the Cape, couldn’t give up the opportunity to come home to witness the move. He remembered the sweep of the beacon shining into his house at night long ago, when the signal was three white flashes and one red. A new beacon, installed in the late 1980s, creates alternating red and white flashes.

Mallory Butler, whose husband Len Butler has stood at the helm of the lighthouse relocation project since its inception two years ago, recalled the many late nights her husband spent in front of a computer and the many unseen hours of preparation that went into the project. When inquired of her role in the project, she laughed and said, “I loaned them my husband.”

Toast to a new home for an old lighthouse. — Mark Lovewell

With the 129-foot move complete, workers will begin replacing most of the metal support beams with wooden blocks, and building up a new concrete foundation between the pad and the lighthouse.

Some of the visitors Saturday had observed all three days of the move — under clouds, blue sky and now fog — and eagerly awaited the final moment. Brian Hays, a longtime visitor from New Jersey, had been planning to see the move since January. When Mr. Hays learned of the accelerated schedule, he immediately made plans to be on the Island. “It was a fire drill,” he said of the process of arranging a dog sitter and booking ferry tickets. He and his wife, Pat, along with their friend June Silvestri, found a small place to stay in Vineyard Haven through Airbnb.

As on Thursday, when the move began, the project site swarmed with filmmakers and photographers, who were by now familiar with the daily routine. Jerry Matyiko, owner of Expert House Movers, holding a cigar in his teeth, began pulling the black pneumatic hoses into place around 10 a.m. Light keeper Richard Skidmore explained to the crowd the move was about to resume. “It’s like watching the minute hand on a clock,” he said.

Suddenly, a small marching band made its way up the dirt path, filling the foggy air with cheerful noises. Mr. Skidmore introduced the Bread and Puppet Circus Band, from Glover, Vt., which later in the weekend performed a benefit for the lighthouse project.

Lighthouse committee chairman Len Butler has christening rights. — Mark Lovewell

As the lighthouse neared the center of the pad on Saturday, project manager Richard Pomroy knelt beside the rollers, carefully placing a few quarters that were easily flattened and stretched by the 500 tons above. He sent some of the quarters home with his daughter Jacqueline Pomroy, who planned to show them to her third grade students at the Atlantis Charter School in Fall River. One day earlier, Mr. Pomroy had given a virtual tour of the project site to the students via Skype.

At around 10:20 the gas generator in a nearby truck started up and the lighthouse was again moving. “Inch by inch, it’s making it’s way,” Mr. Butler said from below the structure.

People lined up against the metal barriers, and also to the right and left, where wooden silt fencing marked the excavation boundaries, and held up their cellphones and cameras to capture the action. Below the lighthouse, a single plumb bob hung down, almost touching the concrete pad, where a nail wrapped in pink tape marked the center of the new location.

Large hydraulic jacks behind the lighthouse did the pushing, and were repositioned every five feet or so. With everything in place for the last push, Mr. Matyiko approached Mr. Butler in front of the lighthouse. He suggested a public auction for the privilege of pressing the lever that would put the lighthouse over the mark. Mr. Butler liked the idea, and approached the crowd.

Standing tall for generations to come. — Mark Lovewell

He started the bidding at $100. Within seconds, the price had reached $700, with Mr. Pomroy himself bidding $800. Former Wampanoag tribal council chairman Beverly Wright raised the bidding to $1,000.

“One thousand going once, one thousand going twice, sold!” Mr. Butler said.

At the back of a large yellow truck parked beside the lighthouse, Ms. Wright lifted the metal lever that activated the jacks for the final few feet of the move. Mr. Butler and others crouched over the nail as the plumb bob slowly approached along a tape measure. Mr. Butler counted off the last 10 inches, to great anticipation, finally yelling “Stop!” with the bob resting gently against nail.

Following rowdy applause, Mr. Butler retrieved a bottle of champagne he had wrapped in burlap, and climbed atop the steel cross beams. Preparing to smash the bottle against the brick wall of the lighthouse, photographers and filmmakers panicked, yelling “Wait!” and scrambled to get a better angle. Mr. Butler moved to the side of lighthouse, facing the crowd.

“I think it’s only fitting that we christen this historic moment and all give a cheer for the final location of the Gay Head Light!” he said, and smashed the bottle, to much cheering and applause.

Workers and lighthouse committee members joined Mr. Butler on the massive beams, and as fog blew past the tower, Mr. Butler uncorked more bottles of champagne.

“Now that’s the hydraulic pressure I like!” said Mr. Matyiko.

“Cheers to the Gay Head Light!” said Mr. Butler, with bottle held high.

Following the toast and continued cheers from the crowd below, the crew and committee members threw their plastic hardhats, as if celebrating a graduation. The hardhats clattered loudly against the rubble and debris below. “Thanks for being part of history,” Mr. Butler said. Later Saturday evening, people gathered at the Aquinnah Old Town Hall for a potluck dinner and celebration.

At the selectmen’s meeting on Tuesday, chairman Jim Newman noted the successful relocation and suggested that the board designate May 30 as a town holiday. Selectman Juli Vanderhoop moved to “have a special day commemorating the lighthouse move and all those who made the effort.” The motion passed unanimously. The day will include a town-sponsored potluck dinner like the one on Saturday.

The selectmen have not yet chosen a name for the holiday, but may do so at their next meeting.

“It’s about the spirit,” Mr. Newman said after the meeting, adding that the efforts to save the lighthouse have set an example for the Island.