A rare opportunity offering true versatility—this beautifully maintained Colonial in East Setauket features a legal, owner-occupied accessory apartment, creating the perfect "two homes in one" setup. Ideal for extended family, guests, or additional income, the private two-bedroom, townhouse-style apartment includes its own entrance, separate deck, modern open layout, and a spa-like bathroom with a soaking tub. Designed for both comfort and independence, it's a standout feature of this exceptional property. The main residence is equally impressive. A welcoming wrap-around porch sets the tone, perfect for morning coffee or hosting guests. Inside, a spacious great room with a fireplace flows seamlessly into a professionally landscaped backyard, complete with an in-ground sprinkler system and a tranquil koi pond—your own private retreat. Additional highlights include an extended driveway accommodating multiple vehicles, owned solar panels for energy efficiency, two separate attics, and abundant storage throughout. The fully finished walk-out basement offers valuable additional living space, ideal for a recreational area, home gym, or media room. With direct outdoor access, it provides flexibility for entertaining, extended living, or creating a private retreat. With a total of six bedrooms and 4.5 bathrooms, this home offers ample space for a variety of living arrangements. Whether you're seeking multi-generational living or the benefit of rental income, this property delivers unmatched flexibility and value. Located in the Three Village School District and close to beaches, hospitals, and universities, this is a unique offering you won't want to miss!