Welcome to 48 River Heights Drive where a tree lined street meets a true custom masterpiece in beautiful North Smithtown. This luxurious 4,800 sq ft home offers 5 bedrooms, 4 baths, a private office, and an incredible blend of high-end design, comfort, and functionality. Custom built, expanded, and fully renovated by the current owner, this home features Brazilian cherry and hardwood oak floors, Pella windows and doors, crown molding, a 400 amp electric service, 4-zone HVAC, central vacuum, full security system, indoor/outdoor Sonos audio, and smart wiring throughout. The heart of the home is the impressive 27x27 chef's eat-in kitchen with custom cherry cabinetry, granite countertops, natural stone backsplash, a massive 13x5 granite island, high-end appliances, 2 dishwashers, 2 sinks, double ovens, and a butler's pantry with additional refrigerator/freezer, sink, storage, and heated floors. The kitchen flows into a palatial 40x20 great room with a natural gas fireplace, built-ins, oversized sliders, and beautiful views of the backyard oasis. The 900 sq ft primary suite is a true retreat with soaring 13 ft ceilings, a spa-like bath, oversized shower, jacuzzi tub, double granite vanities, and a custom walk-in closet. Additional highlights include a second-floor dream laundry room with 2 washers, 2 gas dryers, granite folding counters, a custom office, spacious bedrooms, custom baths, and a newly finished basement completed in 2025. Set on a flat and private .52-acre property, the backyard is an entertainer's dream with an in-ground pool, brand-new liner, granite coping, Italian porcelain pavers, sitting wall, gas fire pit, architectural columns, lighting, and beautiful outdoor living space. Located in the Smithtown Central School District and close to beaches, parks, golf, marinas, restaurants, and shops, this turnkey home offers luxury living inside and out.