Welcome to 20 Emerald Street, a beautifully maintained colonial set on a private 0.86-acre lot in one of Tyngsboro's most desirable neighborhoods! Offering over 3,400 square feet of living space, this exceptional home combines timeless design, flexible living arrangements, and outstanding value. The main residence features a spacious eat-in kitchen, formal dining room, inviting family room, sunroom, and three generously sized bedrooms. A rare highlight is the fully legal accessory dwelling unit with its own private entrance, full kitchen, and full bath—ideal for multigenerational living, extended family, guests, a caregiver, or potential rental income. Recent improvements include a brand-new roof. The landscaped yard offers ample space for recreation and entertaining. Conveniently located near schools, shopping, restaurants, major commuter routes, and tax-free New Hampshire, this unique property delivers the space, flexibility, and lifestyle you are looking for, don't miss it!