On June 25, 1775, William Tryon — the governor of the British colony of New York and a fierce loyalist to the crown — returned to New York City after a yearlong trip overseas. As such, he fully expected to be greeted by a public procession on Broadway.

Tryon disembarked from his boat and was indeed met with a parade, but there was just one problem: It wasn’t for him.

That same day, the new Commander in Chief of the Continental Army, George Washington, had arrived in the city and was met with a hero’s welcome. Adding insult to injury, Tryon was not only forced to wait several hours for Washington’s procession to end, he also had to put up with a crowd jeering — at him.

“Tryon, accustomed to calling the shots in his own colony, must be appalled that this enemy … would parade through Manhattan right under his nose. New York is Tryon’s city, and the public should be cheering for him — not for some usurper,” write Brad Meltzer and Josh Mensch, authors of the new book, “The First Conspiracy: The Secret Plot to Kill George Washington and the Birth of American Counterintelligence” (Flatiron Books), out Jan. 8.

It was at that moment, two months after the start of the American Revolutionary War, that Tryon likely first heard of the army’s formation. He immediately realized that this Washington fellow posed a threat to running his colony his way.

For Washington, Tryon was as dreaded an ­enemy as he’d find: one who would try to end both his life and the burgeoning new nation, embroiling the commander in chief’s housekeeper, and even his bodyguards, in his plot.

And yet, Manhattan still boasts a 67-acre park — home to The Cloisters and some of the city’s most beautiful green space — named for the man who wanted Washington dead.

Tryon was born to an aristocratic family in Norbury Park, England, in 1729. He fought against the French in the Seven Years War before a bullet to his leg in the 1750s ended his military service.

Seeking opportunity in the colonies, he was named governor of North Carolina in 1765. There, he made clear how he would deal with those who defied the crown.

A few years after his appointment, a group of North Carolina farmers organized a revolt against the high fees and taxes they were required to pay to the British. Many of these men couldn’t feed their families, yet the tax was, the authors write, “imposed directly by Governor Tryon, to pay for a vast, lavish palace he was building for himself … This luxurious Governor’s mansion, known everywhere as ‘Tryon’s Palace,’ became a symbol of royal greed and corruption.”

The governor sent a group of mercenaries to meet several hundred of the protesters. “Tryon’s forces overwhelmed the poorly armed farmers, killed or wounded several dozen, and shackled the group’s leaders,” the authors write. “The leaders were quickly tried … for treason.”

Those declared guilty were to be “hanged by the neck … cut down while yet alive … [their] bowels should be taken out and burned before [their] face … [their] head should be cut off, and [their] body should be divided unto four quarters, which were to be placed at the King’s disposal.”

Such was justice under Gov. Tryon, who was transferred in 1772 to New York, where he curried favor with influential families.

And once Washington entered the scene, Tryon was “determined to strike back at the revolutionaries and reassert his power.”

But by fall, revolutionary fervor continued to grow. City leaders were being tarred and feathered by angry mobs, or chased out of town altogether.

Tryon was determined to reclaim his city. “If political solutions fail, then other means are necessary,” the authors write.

New York was not North Carolina, however. Here the rebels were often from powerful families, and the lens of the world was on New York in a way that would not have allowed for a massacre of the sort he had engineered down south.

Instead, he would need to hatch “something secretive, something clandestine.”

Then, as now, “In a city like New York, knowledge is power,” the authors write. So Tryon aimed to infiltrate rebel groups with spies. The first intel he received was that the Continental Congress had authorized the kidnapping of any official hostile to the cause of freedom — and Tryon was their main target.

That second bit of intel turned out to be misinformation — the Congress actually had greater worries about the governor of Virginia — but Tryon believed he was in immediate danger. He wrote a note to New York City’s mayor, Whitehead Hicks, asking that the governing body guarantee his safety, and saying he would flee if this were not granted.

His request was not granted. Worse, Tryon’s leaked letter was printed in a local newspaper. Now, everyone knew that he was yellow-bellied and vulnerable.

So on Oct. 18, 1775, he sneaked out of the Governor’s residence late at night and escaped by boat to a supporter’s home in what is today Flatbush, Brooklyn.

The next day, Tryon and an entourage made their way to the East River and took a ferry to a British transport ship called the Halifax. Several days later, he moved to a larger boat, the Duchess of Gordon, which was docked alongside a 64-gun warship that could guarantee his protection. He was, ­essentially, in self-imposed exile.

By January 1776, Tryon was running an intricate spy network throughout the colonies, and building his own army by paying colonists to switch sides.

Washington was horrified.

Seeing that New York was rife with loyalists sympathetic to Tryon’s cause, Washington came to believe they were as dangerous to the new nation as the British Army.

In early January, he sent his second-in-command, Gen. Charles Lee, to see what he could do to stop Tryon’s activities.

Washington wrote to Lee: “The Tories should be disarmed immediately … you can seize upon the person of the principals … And happy should I be, if the Governor could be one of them.”

Meanwhile, the Congress issued a resolution threatening anyone who traveled to Tryon’s ship with severe penalties — and Washington declared that anyone caught communicating with him would be found guilty of treason.

But even the threat of death could not curb some New Yorkers’ greed.

In February 1776, it was revealed that a hat maker named Thomas Vernon had been meeting with Tryon aboard the floating Governor’s mansion, and had bribed around 50 or 60 of the rebel soldiers to switch sides.

Around this time, a gunsmith named Gilbert Forbes heard that Tryon was paying handsomely for guns, and arranged to deliver 20 to him for a fee equivalent to around $10,000 today.

Soon, Forbes was receiving money from emissaries including David Mathews, a British loyalist appointed by Tryon to replace Hicks as New York City’s mayor. In May, Mathews delivered 115 British pounds from Tryon to Forbes, some of which allowed Forbes to “brib[e] rebel soldiers to join the British cause.”

That same month, a jailed man named Isaac Ketcham told city officials something shocking he’d heard from two inmates.

The prisoners, Michael Lynch and Thomas Hickey, jailed on counterfeiting charges, claimed to be Continental soldiers — but told of a plot connected to Tryon that involved “secretly enlisting men from the colonies to betray their country, with a plan to raise arms against the Continental Army just as the British military forces arrive in New York.”

Horrifyingly for the colonists, the two were also part of an elite squad, the Life Guards, whose sole purpose was to guarantee Washington’s safety. Several of them were preparing to betray their leader, as Lynch and Hickey claimed that other Life Guards were involved as well.

When the Congress learned that Washington, the man holding the promise of this new nation together, was in grave danger, they ordered that Tryon’s men be rounded up.

‘We found five or more of the General’s Life Guards to be accomplices on this wicked plan; which was, at the proper time, to assassinate the person of [Washington] & the other General Officers.’

Mathews was arrested, and one of Washington’s top aides, Samuel Webb, wrote about the plot in his journal, including this passage:

“We found five or more of the General’s Life Guards to be accomplices on this wicked plan; which was, at the proper time, to assassinate the person of [Washington] & the other General Officers.”

The suspected Life Guards and gunsmith Forbes were taken into custody, as was a woman named Mary Smith — Washington’s housekeeper, who was prepared to sell out her boss to the British.

Determined to make an example of the turncoats, Washington ordered Hickey to be tried at once. Found guilty of “mutiny and sedition” and “treasonable correspondence,” he was sentenced to death by hanging.

Washington declared that the execution would take place the following morning, and ordered the entire Continental Army presence in the New York area to attend. At 11 a.m., in “an open field … somewhere near present day Canal Street and the Bowery,” 20,000 people — civilians and military — watched Hickey’s execution.

The worst of the plot had been foiled, as no attempt was made on Washington’s life. Still, many colonists defected to the British Army, which began an attack on New York City in late August, keeping it as their operations base for the seven years until the end of the Revolutionary War.

When New York was officially placed ­under British martial law in November 1776, Tryon finally came off the boat and resumed his official governorship. But with the war raging, Tryon wanted to be in on the action. He was made a general.

By July 1779, however, Tryon’s hubris and cruelty was too much even for the British.

“He leads a series of diversionary raids along the Connecticut coast in which he instructs his men to target unarmed residents and raze inhabited villages,” the authors write. “The raids are brutal, with Tryon’s soldiers allegedly slaughtering civilians, including women and children. After these controversial raids, the American army accuses Tryon of committing war crimes.”

Tryon was never prosecuted for these atrocities. He returned to England and died there in 1788, five years after the British lost the war.

Amazingly, his name is still honored up and down the East Coast. The Tryon Palace in North Carolina — the one over which he massacred farmers — stands as a historic site and museum. In addition to Fort Tryon Park, near the northern tip of Manhattan, there is a street in The Bronx named for him, as well as several streets and buildings in Albany.

While one can question the wisdom of paying any tribute to him, there is no doubting that William Tryon played a significant and fascinating role in the formation of our country.

“From the point of view of the Americans, [Tryon] can only be viewed as a villain,” the authors write. “Nonetheless, he was a man of influence and power, who was often at the center of seismic events. Most important, if his plot was successful, American history — and perhaps America itself — would not exist today.”