Everyone is someone, it’s said, at Casa de Campo.

And such someones.

Dominican real estate tycoons. Venezuelan oil honchos. Cuban American sugar barons. European heirs and heiresses.

“Her husband was the founder of Monster.com; he died,” Rebecca Hughes, who runs a local Web site, CasadeCampoLiving.com, confides one languid tropical afternoon, gesturing matter-of-factly toward a tall woman strolling across a stone walkway.

In this ultra-exclusive, 7,000-acre redoubt — less gated community and resort than gated alternate planet — discretion is everything.

“You’re able to be here without being harassed,” says Leo Proaño, a Dominican realtor and budding film producer who lives in a golf course villa here. “People say we live in this little bubble . . . but security is very important to us.”

Casa de Campo’s cloistered mystique adds a measure of intrigue to the scandal that’s complicating life for Sen. Robert Menendez, the New Jersey Democrat and newly minted chairman of the Senate Foreign Relations Committee. Menendez got the VIP treatment, winging down to Casa de Campo a couple of times in 2010 on the private jet of a buddy and campaign contributor, Florida eye doctor Salomon Melgen, who owns a villa here.

Then — whoops — early last month, Menendez forked over $58,500 to cover those flights, because lawmakers aren’t supposed to accept those sorts of freebies. Then — even less conveniently — later in January the FBI raided Melgen’s West Palm Beach office, although it’s not clear what triggered the investigation; a lawyer for Melgen has said law enforcement officials have not clued in his client, either.

Now Menendez is getting questions about his role in pushing for the Dominican Republic to honor a lucrative port security contract awarded to a company with ties to Melgen. Rivals were pretty cranky about the deal since, after all, Melgen is known more as a rich doctor than a security expert.

On top of all that, Menendez has denied allegations that he cavorted with prostitutes, including an underage hooker, during his Casa de Campo jaunts, suggestions that the senator has vigorously denounced as “smears.” (The allegations — made by an anonymous whistleblower and first publicized on a conservative Web site — have not been verified independently.)

Prostitution is legal in the Dominican Republic, though not for underage girls. But “it’s not socially acceptable” in Casa de Campo and is seldom flaunted, says a longtime Dominican resident. The resort’s vibe tilts much more toward decorum — you wouldn’t even go to lunch unless suitably attired — than the anything-goes bacchanalia that defines some Caribbean getaways. Security guards diligently turn away anyone who looks to them like a prostitute. Never mind those occasional, uncomfortable instances when a resident has been mistakenly blocked from entering because she was provocatively dressed, several longtime residents say.

In the scruffy neighboring ­sugar-mill town of La Romana, prostitutes cluster in strip clubs with private “party” rooms upstairs. On a recent night, a dozen swarmed a visitor to one of those clubs. They preened in skintight skirts so short that they hid almost nothing; they gyrated their hips, clutched their breasts and pouted their lips. “How about me?” “What would you like?” “Let’s have a drink, sweetie.”

The prostitutes talk of occasionally being secreted into Casa de Campo in the back seats of chauffeur-driven SUVs with tinted windows, gliding into the complex past a large, thatched-roof security checkpoint after the swipe of a card opens the gate. A 27-year-old prostitute recalled a four-day job at a Casa de Campo villa for which she collected $500 a night instead of her regular $170. She shed her usual plunging necklines and lacy peek-a-boo tights in favor of more subdued dresses. “I looked very respectable,” she said.

Golf, helipads and polo

Casa de Campo, which lies on the picturesque southeastern coast of the Dominican Republic about 11 / 2 hours from Santo Domingo, began as a getaway for executives of Gulf+ Western. The company operated La Romana’s sugar mill, once the world’s largest.

In the early 1970s, famed golf course designer Pete Dye conjured an 18-hole marvel called the Teeth of the Dog, which has sweeping seaside views and has been named the best course in the Caribbean by Golf magazine. A round can set you back as much as $250, plus tax, though half that much if you’re a resident and well worth it at any price, devotees say. “There’s nothing like it,” says Lou Gilmore, a Pennsylvania businessman who winters at a villa he owns here.

Oscar de la Renta, who once owned a home in Casa de Campo, provided input about the overall “ambience” of the development, according to an official history.

The property is now owned by a corporation controlled by the Fanjul family, Florida sugar moguls and Olympic-size political campaign donors. The Fanjuls’ villa is called Casa Grande, which means “big house,” and “it’s no exaggeration,” says Phil Silvestri, a longtime resident, who notes that the Fanjuls’ place has its own helipad, natch.

Moneyed Santo Domingans, the ones who don’t have their own helipads, can still chopper in, touching down at the regular helipad — next to the polo grounds. Foreigners arrive in fleets of private jets at a major airport 10 minutes away. The commercial planes that bring golf-obsessed business owners and executives, with well-defined ankle-sock tan lines to prove it, are almost an afterthought in the blizzard of private-jet bling.

Guests at the retreat’s plush spa hotel — where rooms were going for between $495 and $1,800 a night recently — buzz around the manicured grounds in personal gas-powered golf carts. But they can’t keep up with the villa owners (and their children) who tear down the streets in huge, souped-up golf carts, with windshields, that can touch 30 mph.

Mansions of staggering dimensions and architectural variety dot quiet streets where orchids, bougainvillea, flowering flamboyant trees and palms thrive: Italianate villas, Mediterranean behemoths with barrel-tile roofs, Balinese-style jaw-droppers with expansive ocean views. Some require up to 18 staffers, small armies of cooks and maids, and even the most humdrum of the estates invariably have at least four to six attendants, says Proaño, who produced the upcoming film “Cristo Rey” when he wasn’t busy managing and selling villas in Casa de Campo.

Famous faces catching rays

Former defense secretary Donald Rumsfeld once owned a home here, and local realtors say Dominican baseball MVPs Sammy Sosa and George Bell have, too. Former president Bill Clinton and both presidents Bush have been spotted here. The list of celebrities who have vacationed within Casa de Campo’s gates is too long to print. But how about Michael Jackson, Beyonce, Jay-Z and, of course, Kim Kardashian? Actor George Hamilton has popped in to nurture his perma-tan.

Hughes and Silvestri have found themselves at dinner parties with the likes of Richard Branson and Vincent Cerf — you know, the guy who sort of invented the Internet. “At lunch one day, the conversation was about aeroplanes,” Hughes says in her British accent. “And not just aeroplanes, but about buying aeroplanes, and what a great investment they are, and how you can just buy them and flip them.”

One ocean-side property is being offered for $20 million. Just for the lot. No house included.

“You know the American dream is the white picket fence? The Dominican dream is a villa in Casa de Campo and a Mercedes,” Silvestri says.

The villa that Citizens for Responsibility and Ethics in Washington has identified as the possible vacation pad of Sen. Menendez’s pal, Melgen, perches on a winding street next to the private La Romana Country Club, an enclave within an enclave, open only to members. The salmon-colored villa sprawls beneath palm trees, an enviably luxurious residence but merely middle-class by Casa de Campo standards. A stone exterior wall provides extra privacy.

Just a few minutes away by golf cart, locals and villa renters saunter to the beach down a path lined by speakers disguised as rocks. Soothing spa music trickles out. Squadrons of attendants in white shorts and caps fuss over beach chairs, positioning them just right for the smattering of couples and families luxuriating in the sun. A svelte young woman slips out of her bikini top and stretches out on a cushioned lounge chair. A bodyguard in mirrored sunglasses keeps watch at a discreet distance, surely one of the easier assignments ever, since crime seldom occurs here.

Others sip prosecco at the edge of the sand at the Beach Club by Le Cirque, where the menu was designed by a chef from the New York original. At the bar, the club’s finest Montecristo cigar goes for $27.

Men in linen shirts and women in tasteful printed dresses are scattered about the tables on the veranda, some enjoying the perfectly grilled Patagonian toothfish encircled by a rich drizzled seafood sauce.

The conversations keep to a low hum until, at a tucked-away table, a dark beauty in Jackie O. sunglasses exclaims, “She’s just a trophy wife!”

The diners barely take note. They’re too busy relaxing.