Step into a world of timeless elegance and unparalleled prestige at The Mallows — the crown jewel of the North Shore and one of the most exclusive waterfront estates in Head of the Harbor Village. Originally commissioned by the illustrious Astor family and masterfully designed by acclaimed architect Charles Platt, this historic masterpiece sprawls across 4+ acres of exquisitely landscaped grounds with over 300 feet of private beachfront on Stony Brook Harbor, offering commanding west-facing sunset views that stretch across the Long Island Sound to Connecticut. This is more than a residence — it's a statement. A sanctuary where Gilded Age grandeur meets refined modern luxury. From the moment you arrive, you're greeted by an enchanting cobblestone driveway and sweeping limestone patio that set the stage for a resort-style lifestyle. Outdoor amenities rival the finest private clubs—a heated saltwater pool, hot tub, private tennis court, waterfront gazebo, and serene gardens including a vegetable garden and charming chicken coop, all thoughtfully curated for entertaining and tranquility alike. Inside, the estate unfolds with 11 bedrooms, 5.5 bathrooms, and 14 fireplaces, all artfully restored to preserve the home's stately character while embracing contemporary sophistication. A 3-bedroom guest cottage offers additional space for hosting in luxury. Every inch of this estate speaks to craftsmanship and distinction: soaring 9.5-foot ceilings, rich custom millwork, an elegant library, and a breathtaking glass conservatory off the primary suite, framed by hurricane-rated Marvin windows and doors. A four-season glass room seamlessly extends from the family room, offering panoramic harbor views year-round. Entertain in grandeur with a professional-grade chef's kitchen equipped with Viking appliances, Sub-Zero refrigeration, and a gas range—adjacent to a formal dining room designed for unforgettable gatherings. Additional luxuries include a three-level elevator, a sprawling wine cellar, and every detail one would expect in a world-class estate. Perfectly positioned just moments from Stony Brook Yacht Club, Avalon Nature Preserve, Stony Brook Village, and LIRR access, this remarkable estate also falls within the award-winning Three Village School District. The Mallows is more than a home — it's a generational legacy, an iconic waterfront retreat, and a once-in-a-lifetime opportunity to own the most coveted estate on the North Shore.