Many of these rooms, like the Jackie Gaughan suite, have exceptional histories or aesthetics.
At the Warwick New York in Manhattan, there is a corner suite named after Cary Grant, who lived there for 12 years. From the hallway, it resembles any other room. Inside, guests find a wraparound terrace and wood furnishings and floral curtains similar to what Mr. Grant, or other famous guests like the Beatles, would have enjoyed. Many people learn about the room from previous guests; it can be booked by contacting Angela Calabrese, the director of reservations. “This is what hospitality is all about,” she said, “having some secrets we only share with our special guests.”
Union Station Hotel in Nashville has Room 711, where a ghost named Abigail is said to linger. The property was once a train station, and according to one legend, Abigail threw herself in front of a train there after losing her lover in World War II. While the rest of the hotel has a modern, chic design, this room comes with antique furnishings like a four-poster bed and artwork inspired by her tale.
Only guests who know about this legend request to stay in her room. It’s a selling point, said Kate Thompson, the director of sales and marketing. “What better way to intrigue and delight guests than give them an unexpected twist on the experience.”
Other secret rooms come with features or amenities unavailable to other guests.
Ed Valente, a financial services professional who splits his time between São Paulo, Brazil, and Milan, visited the Uxua Casa Hotel and Spa in Trancoso, Brazil, almost a dozen times before learning there was a private, unlisted villa. It was offered to him when the hotel was fully booked, and he was surprised by not only its existence but also its near invisibility to other guests (it is inside a garden). “When you come and go, you almost feel like you’re popping out of nowhere,” Mr. Valente said.
Named Casa Frozina after a beloved local who called it home, the villa comes with an outdoor hot tub, a spacious veranda, a garden with sofas and hammocks, and furnishings made by a local artisan. Guests staying there even get access to a camouflaged path that leads to the town square.
Suite 5000 at Mandarin Oriental, New York features a private art collection, a Swarovski crystal wall, a curated record collection and floor-to-ceiling views of Central Park. It, too, is available only to those who know about it (travelers can request it when they call to make a reservation).
Once guests land one of these secret rooms, most face the dilemma of whether to keep them secret. Should they boast about their experience on social media or retain the intrigue for future guests? “Honestly, I try to keep it to myself,” Mr. Valente said. “After all, a secret should not be shared to many, only to those in the know.”