Experience timeless elegance and unparalleled beauty at this historical landmark in the exclusive Head of the Harbor Village. "The Mallows" was custom-built by renowned architect Charles Platt for the esteemed Astor family. Situated on over 4 meticulously manicured acres, this North Shore waterfront home boasts more than 300 feet of pristine beachfront, offering breathtaking, western-facing sunset views over the stunning Stony Brook Harbor. Enjoy the tranquility of your own private beach, complemented by a heated saltwater swimming pool and hot tub, with panoramic views of the Long Island Sound extending to Connecticut. The property features luxurious outdoor amenities, including a private tennis court, a charming gazebo at the water's edge, a massive cobblestone driveway, a delightful chicken coop, a vegetable garden, and a sprawling limestone patio perfect for entertaining at your own outdoor oasis. Inside, the grand residence offers 11 bedrooms including a 3-bedroom guest cottage, 5.5 bathrooms, 14 fireplaces, conveniently located three-level elevator, a sophisticated library, and lofty 9.5 foot ceilings adorned with custom millwork. Notably, an all-glass conservatory adjoined to the primary en suite, equipped with Marvin hurricane-proof windows and doors, captures every angle of the panoramic sunset. The first-level glass all-season room off the family room ensures year-round enjoyment of the stunning views. The gourmet kitchen, equipped with Viking appliances, gas stove and a Sub-Zero refrigerator, is perfect for culinary exploration, entertaining and is conveniently located off the expansive dining room which exudes a sense of grandeur and elegance. Seamlessly integrating modern amenities with classic architectural elements, this estate is ideally located walking distance to the Stony Brook Yacht Club, Avalon Nature Preserve, and Stony Brook Village. Situated within close proximity to the LIRR, North Shore beaches, and the award-winning Three Village School District, making it the perfect sanctuary for discerning individuals who appreciate the finer things in life.