Connecticut, 1781. New London is burning after British troops — led by Benedict Arnold — raided the town. Dozens of people are dead. Hundreds are hurt. The sky is full of smoke.

About a month later, soldiers fight in Yorktown, Va., in the last major battle of the Revolutionary War. A rallying cry: “Remember New London.”

And 242 years later, New London has not forgotten.

On a recent Saturday evening, hundreds of people gathered in the streets to burn Benedict Arnold, America’s most famous traitor, in effigy. To the beat of a fife and drum, residents marched the life-sized, two-faced puppet to its execution. Some, in tricorn hats, carried mock bayonets. Others held torches.

“Burn the traitor!” onlookers screamed. “Burn him!”

The procession is an annual piece of street theater, organized by Flock Theatre, a New London troupe.

Organizers started it in 2013, reanimating a tradition from the 18th and 19th centuries, and hoping to spark interest in local history. New Londoners used to burn Arnold in effigy every year around Sept. 6, the day he torched their ancestors’ homes and shops. Other cities did, too.

All these years later, participants find an unlikely sort of satisfaction in the ritual.

“The town that Benedict Arnold burned now burns Benedict Arnold,” said David Calder, a senior lecturer at the University of Manchester, who researches street theater. “But rather than that being a vindictive, vengeful thing, it seems like it’s this very playful, triumphant statement of survival and continuity.”

Benedict Arnold’s name has become synonymous with treason in the generations since the American Revolution, even if the particulars are sometimes forgotten.

Arnold was born in 1741, grew up in Norwich, Conn., and initially fought against the British. He rose to the rank of major general. But as the war dragged on, he began feeding information to the British and plotted to surrender West Point in exchange for a bribe. Ultimately, he defected.

His betrayal crushed George Washington, the leader of the American troops, said Eliot A. Cohen, author of “Conquered into Liberty,” a book about early American military struggles: “If Arnold could be a traitor, who could we trust?”

To remember the complexity of the man, New London does not burn the whole puppet. Instead, it saves a leg — where Arnold was hurt fighting for the Americans. “It’s honoring one part of him and really vilifying the other,” said Derron Wood, the executive artistic director of the theater group.

In New London this month, some participants said they could imagine the streets around them burning — the hot air that would have scalded their throats, the screams of fear, of pain, that may have risen from out of the buildings around them.

“It was an absolute tragedy, like Maui,” said Michael Passero, the mayor of New London, referring to the wildfires on the island last month. “Everything they knew was gone.”

Some of the marchers tried to imagine the rage and grief people must have felt at Arnold’s betrayal.

“This fellow, who we thought was one of us, he turns on us,” said Robert Lecce, who works as a historic re-enactor at the Leffingwell House Museum in Norwich.

Mary Harris, 66, of Ledyard, was marching with a sign that said “Burn the Traitor.” She drew a connection to the rioters at the U.S. Capitol on Jan. 6 and to former President Donald J. Trump.

“Do you know who that really means as a traitor?” she said. “You know, the indicted guy?”

Alexandra Clancy, dressed in a pink gown and white cap, said she grew up in Norwich, across from where Arnold once lived. Until recently, she did not know that New London had burned.

“That’s the great thing about being in New England,” Ms. Clancy, 40, said. “All the Revolutionary things happened right here. I love the West — they don’t have what we have.”

The tradition has roots that go back even further than Benedict Arnold. Many 18th-century Americans — former Britons — had treasured Guy Fawkes Night, when bonfires blaze each year to mark his attempt in 1605 to blow up the British Houses of Parliament.

But having just overthrown the British government, the American revolutionaries had no inclination to keep burning effigies of Fawkes. So they burned Benedict Arnold instead.

“We needed a traitor,” said Steven Manuel, the executive director of the New London County Historical Society. “And Arnold was a really convenient traitor.”

Even if Arnold wasn’t the only traitor during the Revolution, for the first 100 years of the country’s history, historians said, he was a useful meme for an America trying to cement its unity.

Before Mr. Passero touched a lit torch to the Arnold effigy, he asked the crowd to honor the people who died fighting in the Revolutionary War. They fell silent as they stood facing Fort Griswold Battlefield State Park just across the Thames River, where dozens of young American men had died fighting Arnold’s troops.

Then the traitor took his last look before the flames began licking his red coat, turning him into an orange blaze high above the jeering crowd.