Https://www.twinpine.com. Twin Pine Casino & Hotel is located in Middletown, California-conveniently situated at the northern gateway to the world famous Napa Valley. Our state-of-the-art facility has over 92,000 square feet of guest space and is open 24 hours a day, 7 days a week. Our unique turn-of-the century winery theme makes us one of the most popular hotels near Napa Valley.