Which borough is a hotbed for haunting?

A paranormal expert tells The Post that Gotham’s “most maligned borough” is also the eeriest.

Andrea Janes is the founder of Boroughs of the Dead, an independent, female-led tour operator that takes visitors on macabre history tours of NYC.

She said that “if you’re really serious about ghosts and want to know where most of them are,” there’s only one place to boo out: Staten Island.

“It’s wall-to-wall ghosts,” she underscored, noting that the home of Pete Davidson is also dotted with haunted mansions, asylums, forts and fields.

Part of the ghostly lore comes from the borough’s history as a plague isolation unit: Janes notes that over the last several centuries, Staten Island has served, to varying degrees, as a quarantine colony.

“If you ask me what is the most haunted place in Staten Island, I would say the entire island,” she said.

Quarantine machine

In 1799, city officials decided to keep deadly diseases like yellow fever and smallpox farther afield from the city’s bustling ports.

The resulting New York Marine Hospital, known ominously as “The Quarantine,” stayed open until 1858, when local opposition, fueled by fears of contagion, culminated in an attack that burned the complex to the ground.

“Maybe that’s why the island is so haunted,” Janes theorized.

Even with the OG hospital reduced to ash, Staten Island couldn’t stay clear of the quarantine game.

In 1905, the island’s second-highest point became a tuberculosis quarantine facility. The resulting Sea View Hospital, opened in 1913, offered upper-class patients the prescribed treatment of fresh air, sunlight, and healthy food.

Of course, no amount of fresh air or fiber could save the doomed patients.

The College of Staten Island

The hospital sites may be dismal, but Janes shared there’s one place on Staten Island that’s even worse — and so disturbing, she told The Post, that she never puts it on her haunted itinerary.

“The College of Staten Island is on the former site of the Willowbrook State School,” she told The Post.

“That’s a place I wouldn’t go with a tour group because it’s too sad.”

Willowbrook originally opened in 1948 as the largest institution in the world for the treatment of people with developmental disabilities.

In 1972, Geraldo Rivera documented its deplorable patient conditions in the award-winning expose, “Willowbrook: The Last Great Disgrace,” which revealed children — some of whom were subject to depraved medical experiments — left in extreme filth, overcrowding and neglect.

The conditions at Willowbrook were so horrifying that they allegedly inspired the gory 2012 masterpiece “American Horror Story: Asylum” with Sarah Paulson and Jessica Lange.

Willowbrook closed in 1987, and a portion of the property became the College of Staten Island in 1993.

While most buildings have been converted into classrooms and offices, underground tunnels still connect them, and rumors of hauntings understandably persist.

The Billop Conference House

“There’s some kind of convergence of psychical activity right over Staten Island that I cannot describe,” said Janes, naming the Billop Conference House as one of the oldest sources of unease.

The house, which dates to the late 17th century, served as a meeting place for peace talks between American colonists and the British in the fall of 1776, but the “conference” that gave the house its name never led to a resolution, and fighting continued.

The house may be most famous for the legend of a servant girl murdered by Christopher Billop, the home’s paranoid, crown-loyal patriarch, along with several other rumors of bloodshed and betrayal.

But none of the connected crimes have been substantiated with historical evidence.

Still, visitors claim to have seen apparitions of a servant girl, along with the marauding forms of British soldiers.

Neighbors also attest to hearing a man singing or shouting and a woman screaming.

Curiously, these apparitions may predate the building itself:

The Conference House grounds include a stretch of land known as Burial Ridge, the largest pre-European Native American burial ground in New York.

Fort Wadsworth

Fort Wadsworth, a 226-acre public park situated on Staten Island’s northeastern coast, holds the record as the longest-serving active military post in U.S. history.

But that illustrious distinction has given rise to strange sensations.

“There’s something weird going on there,” Janes attested.

Visitors to the fort, which was turned into a park in 1994, have reported seeing apparitions of fallen soldiers moving through the walls and even driving old cars.

Visitors have also reported hearing disembodied footsteps, gunshots and cannon blasts.

Then there’s the smell of tobacco smoke that seemingly comes from nowhere — or cooking aromas even though there’s literally no kitchen on site.

Kreisher Mansion

For the most haunted spot in Staten Island, Janes calls out the Kreischer Mansion on Arthur Kill Road.

“It’s very haunted,” she emphasized.

German brick magnate Balthasar Kreischer built the gabled mansion in 1885 for his son, Edward.

But nine years later, Edward was found shot dead behind his father’s brick factory across the street.

Unsure whether Edward’s death was a murder or a suicide, his grieving family members sought the help of spiritualists, holding seances in the home, which some say opened up portals that would have been better left closed.

In 2005, the Kreischer Mansion played host to the grisly mobland killing of Bonanno crime family associate Robert McKelvey.

Along with three other mob members, Young stabbed and strangled McKelvey before dismembering his body and burning his remains in the mansion’s furnace.

The house’s grim history helps explain some of its alleged paranormal activity.

Visitors have claimed to see apparitions in the windows and furniture moving of its own accord — and hear pots and pans clattering in the kitchen, plus a lone, harrowing cry emanating through the home.

Boroughs of the Dead celebrates its 13th anniversary this October. The para-curious can book a tour here and catch Jane on October 27th at the Center for Brooklyn, where she will appear as part of the panel discussion: Haunted Brooklyn: Ghosts, Folklore and the Stories We Tell.