"Did you just see something in the window?" he asked. She felt a chill.

They saw her only once. That was before Linda Roberts-Antinoro and her husband, Mike Antinoro, had moved into the historic stone house surrounded by sloping hills and a scenic stream.

As they visited the Baltimore County property on a blustery afternoon in January 1990 and stood gazing at the locked and empty home, they noticed a shadowy figure in the window above the front door.

Linda didn't say anything. Her husband was a New York City firefighter, a no-nonsense type of guy. It's probably just reflections of trees, Linda told herself. But then Mike turned to her, perplexed: "Did you just see something in the window?" She felt a chill.

During the more than 25 years they lived there, they grew accustomed to the occasional sound of footsteps above them when no one was upstairs, or the inexplicable relocation of a candle from the fireplace mantel to other corners of the room.

And - well, that's the whole story. Linda and Mike never actually saw their ghost again.

For all our delight with horror films and supernatural folklore, the rather underwhelming truth about many real American ghost stories is that they're just a wee bit . . . boring. Too subtle or ambiguous, really, to become the stuff of legend. Yet these are the most ubiquitous: Most of us know someone who thinks they once saw something.

About 45 percent of Americans believe in ghosts, according to a 2013 Huffington Post and YouGov poll; Pew research shows that 18 percent of American adults are convinced that they've seen or been in the presence of a spirit.

Colin Dickey, author of "Ghostland: An American History in Haunted Places," and his wife host annual ghost-story parties. "Everybody's a bit skeptical, until the first couple of stories come out," he says, "and then everybody seems to have a story. That's kind of the enduring popularity of this genre, because for so many people, they have, somewhere in their history, something they can't quite explain, but yet don't want to dismiss out of hand."

Ashley Jones, a 28-year-old arborist from Gaithersburg, is one of them. She grew up as one of 15 cousins who spent a lot of time at her grandmother's historic farm on Maryland's Eastern Shore.

As a child, she often slept in a front room of the farmhouse. That's where she once woke in the middle of the night and glimpsed a whitish, translucent figure of a man striding past her, wearing a uniform-like suit and a top hat. On another occasion, she awakened to see the same apparition, this time accompanied by a ghostly woman in a long gown. On both occasions, she says, she forced herself to close her eyes and go back to sleep, convinced that it must have been a lingering fragment of a dream.

"I didn't want to be seen as the nut in the family, so I didn't bring it up to anyone," Jones says.

But things kept happening in the house, she says - a Christmas train set that suddenly started running without anyone turning it on, the sound of creaking stairs when no one was walking on them. Then one of her younger cousins, who had slept in the same front room of the house, announced one morning that she woke in the night and saw a pale, shimmering man sitting on the hearth, wearing a top hat.

"My stomach dropped," Jones recalls. "There was no way, with nobody knowing what I saw, that she would come up with that exact same outfit for the guy."

Jones never knew the exact history of her late grandmother's farmhouse, which was sold last year, or the identities of residents who might have lived there long ago.

But Dickey thinks many ghost stories are ultimately ­fueled by our curiosity about those who have gone before us - that hauntings ultimately reveal more about the person who perceives the phantom than the phantom itself.

"If it's a house where there's not a famous haunting - maybe it's not a well-known property, and yet it's been around since the 19th century and has changed hands a number of times - I think there is for many of us this sense of wanting to feel connected to that past," he says. "We want a connection to a history that we perceive but feel is just out of reach, and ghosts are a really common way for us to express that."

In some cases, that history is more clearly defined. Fay Hobbs Manthey has always known that her home, an apartment on the third floor of a historic building on North Fairfax Street in Old Town Alexandria, was the setting of a tragedy in 1879. Laura Schafer died there on her wedding day, when the embers of a fire set her gown ablaze as she dressed for her ceremony. The building, which Manthey has owned for 15 years, is a popular stop on local ghost tours.

Other visitors - and especially tenants in the commercial space downstairs - have reported a slew of bizarre experiences: strange noises, whooshing air, extreme coldness or heat.

And yet, Manthey has never witnessed any of that herself.

"I don't doubt that Laura's here, I really don't," she says. "It's just a gut feeling, and because I know the history."

Jennifer Cornell, who works in business development in Orlando, is similarly certain that the former resident of her rented 1920s-era bungalow is still around. A neighbor across the street told Cornell all about Ella, the elderly widow who had lived and died in the house in the late 1960s, even sharing photographs of the kindly former schoolteacher.

That helped Cornell make sense of certain inexplicable phenomena in Ella's former home. Cornell once watched a heavy bath towel swing wildly on a hook, "but there wasn't a draft in the house," she says. Her dogs would sometimes pace and stare in an empty backroom, as though they were watching someone. Lights would occasionally shut off for no discernible reason.

But Cornell found all of this oddly comforting: "I've always felt protected here," she says. Now, the house has been sold and will soon be demolished, and Cornell is thinking of moving to New York. "I've already told Ella that she can come with me if she wants," she says.

Last fall, Linda and Mike bade farewell to their own allegedly haunted house, retiring to another home in Maryland. The property is still on the market, Linda says; when it sells, she will pass along the records she's kept about the original owners of the house, who are rumored to have offered shelter to runaway slaves on the underground railroad. As for the less tangible aspects of the house's history - Linda hopes a prospective buyer won't be thwarted by the possibility of a benign, if supernatural, presence.

Linda's skeptical husband once devised his own test to determine whether there truly was an all-knowing spirit hanging around.

"He left a Powerball ticket out, with a pencil," she says, "but the ghost never filled it out for him."