In Lafayette, a distinguished East Bay enclave celebrated for its high quality of life, oak-studded hills, mild climate, and strong sense of community, 3621 Chestnut Street emerges as an uncommon multifamily offering. Multi-family properties in this area trade infrequently, given the dominance of single-family residences in the local market, making this three-unit setup a distinctive prospect for those pursuing reliable income streams or owner-occupancy in a setting of enduring appeal. Encompassing 1,426 square feet on a 4,550-square-foot lot across two stories, this duplex with a newly constructed detached ADU emphasizes privacy and functionality. The main duplex includes Unit A (2 bedrooms, 2.5 bathrooms) and Unit B (1 bedroom, 1 bathroom), each with separate entrances, in-unit laundry, upgraded bathrooms, and kitchens equipped with granite slab counters and gas cooktops. Modern conveniences such as central heating and air conditioning, a tankless water heater, and separate utility meters facilitate efficient tenant management. The detached ADU provides an additional 1-bedroom, 1-bathroom space, complemented by a large fenced yard featuring a patio and garden area for outdoor enjoyment. Ideally positioned with a Walk Score of 92/100, the property offers walkable access to downtown Lafayette's boutiques and eateries, the BART station for efficient regional travel, multiple shopping centers within 0.4 miles, top schools, freeways, and nearby recreational opportunities in Mount Diablo State Park. The Lafayette Elementary School District and Acalanes Union High School District boast exemplary schools, including Springhill Elementary, Happy Valley Elementary, and Campolindo High School, known for their outstanding performance and supportive environments. Fully leased and income-producing, Unit A is rented at $2,475 per month through October 31, 2025; Unit B at $2,300 per month through September 30, 2026; and the ADU at $2,995 per month through August 10, 2026. With Lafayette's reputation for safety, conservation efforts, and a welcoming community spirit, 3621 Chestnut Street presents a prime opportunity in a market where such properties are truly exceptional. Furthermore, the neighboring property at 3615 Chestnut Street—a modern two-unit duplex built in 2014—is also on the market, offering a rare opportunity to secure both adjacent lots for greater scale and versatility.