Among the notable additions is CordeValle in San Martin, Calif., part of the L.V.X. Collection. This 1,700-acre luxury resort features 45 guestrooms and residential-style Fairway Homes; an 18-hole golf course designed by Robert Trent Jones, Jr.; restaurants; a spa; an estate winery; and tennis and pickleball courts.

Another highlight is Farol Hotel in Cascais, Portugal, also part of the L.V.X. Collection. This boutique hotel blends a 19th-century mansion with contemporary architecture and boasts 33 guestrooms and suites, some with 180-degree ocean views. Other features include two restaurants and bars, plus an outdoor saltwater pool.

The Himalayan Wildlife Sanctuary in Chitwan, Nepal, part of the Lifestyle Collection, offers a secluded escape amid the wilderness. It features 27 guestrooms and villas, authentic Nepali and international cuisine and access to Chitwan National Park.

"We are proud to welcome this distinctive group of 15 new member properties, including six new openings, to our global portfolio of luxury independent hotels," said Lindsey Ueberroth, CEO of Preferred Hotels & Resorts. "Presenting our loyal customers and community of passionate travelers with new places of distinction and opportunities to discover the latest luxury independent hotel experiences is core to our brand promise, 'Believe in Travel.'"

Other new additions include Hotel Mousai Cancun in Mexico, Hotel Ambasador Split in Croatia, Durango Casino & Resort in Las Vegas, Pendry Natirar in New Jersey and more.