200 Route 9A Exceptional residence featuring a fully legal accessory apartment, offering rare flexibility for multigenerational living, extended family, guests, or private professional space. The thoughtfully designed additional living area includes its own entrance, kitchen, bath, and living quarters, creating a comfortable and private environment while maintaining the character of a single-family home. Approximately 900 sq ft of finished lower-level space enhances the home's functionality beyond the main living area reported in municipal records. Tucked away at the end of a semi-private road in a peaceful neighborhood, this property combines privacy, versatility, and elegant design. The main residence features 3 bedrooms, hardwood floors throughout the living areas, spacious living and dining rooms, and a dramatic vaulted fireplace that serves as a warm and inviting centerpiece. The chef's kitchen boasts a Wolf range with built-in grille, double oven, and Sub-Zero freezer-ideal for both everyday living and entertaining. Step outside to the expansive Ipe Brazilian walnut deck with a large overhead awning for seasonal indoor/outdoor comfort. The resort-style backyard is a private oasis with a heated pool, Caldera spa, and lush landscaping-perfect for relaxing or entertaining. A 3-car garage with a workshop area provides ample space for vehicles, storage, and hobbies. Central air conditioning ensures year-round comfort. Located just 5 minutes from the Croton-Harmon Metro-North Station with a 40-minute express ride to NYC, this home offers the ideal balance of luxury, convenience, and tranquility in one of Ossining's most desirable hidden neighborhoods.