This magnificent new build is perched on its own mountain, overlooking 138 acres of manicured golf course and 135 acres of park reserve on three sides. Just north of $5-6.5MM new constructions on 1-2 acre plots, this 5-acre private estate offers one of the most impressive settings on the market, surrounded by 273+/- acres of protected golf course and reserve vistas. The home spans 3 stories, with 10,500 +/- feet of living space. High ceilings, 16' sliding glass doors, a glass wall system and transom windows contribute to a unique sense of light and volume. Other special features include 2 true master bedroom suites (both 1st and 2nd floors), an elevator, pre-wired theater, gym, wine cellar, 45' pool, hot tub, sunbed, fire pit and tennis. This is a green home, with solar, foam insulation and LED lighting. And a smart home, with a 26-speaker sound system, video surveillance and remote heating, cooling and pool systems. Located in Sag Harbor's exceptional school district, minutes to Long Beach, and equidistant between Southampton, Sag Harbor, Watermill and Bridgehampton.