559 4th Avenue a/k/a 133-135 16th Street presents a rare mixed-use investment and development opportunity in the heart of the rapidly transforming Park Slope/Gowanus corridor. Situated on a prominent northeast corner lot, this income-producing property combines strong existing infrastructure with significant future upside through additional buildable square footage. The property sits on a 20 ft x 90 ft lot with a current built area of approximately 5,346 square feet and building dimensions of 20 ft x 90 ft. Zoned R8A / C2-4 within the Enhanced Commercial District - 1 (EC-1), the site offers substantial development potential Maximum buildable area of approximately 10,836 square feet, leaving additional buildable area available. Zoning & Development Highlights: Residential FAR: 6.02 Facility FAR: 6.5 Current FAR: 2.97 Max Buildable Area: 10,836 SF Current Built Area: 5,765 SF Property Features: Four residential rental apartments One basement studio unit Finished basement with kitchenette Two vacant commercial storefronts Two-car garage with electric garage door Most residential units to be delivered vacant Regular-shaped corner lot with northeast exposure Ground elevation: 54 ft This versatile mixed-use asset offers exceptional flexibility for investors, developers, end-users, or 1031 exchange buyers seeking immediate income with long-term redevelopment potential. The combination of vacant commercial space, residential units, garage parking, and unused FAR creates multiple value-add strategies ranging from luxury rentals and condominium conversion to mixed-use redevelopment or owner-occupancy. Perfectly positioned along bustling 4th Avenue with close proximity to transportation, retail corridors, dining, and the ongoing growth surrounding Gowanus and South Brooklyn, this is an opportunity to acquire a strategically located property with both stable fundamentals and meaningful future upside.