New construction modern farmhouse with ADU and expansive level grounds in one of Mill Valley's most desirable locations. 308 Marin Avenue offers a rare blend of design, functionality, and flexibilityideal for today's lifestyle. The property spans approximately 2,599 sq ft (per measurements) and includes a 4BR/2.5BA main residence plus an attached ADU above the garage. The main home features a light-filled kitchen that flows seamlessly into open living spaces and a generous family room, ideal as a media room, playroom, or secondary lounge. A well-appointed pantry and dedicated laundry room add everyday convenience. Large openings create a seamless indoor-outdoor connection to expansive front and rear yards with substantial, level lawn areasan increasingly rare offering in Mill Valleyperfect for entertaining, recreation, or relaxation. The attached ADU provides a fully independent living space, ideal for guests, extended family, a home office, or potential income. Clean lines, warm finishes, and a functional layout define the home's modern farmhouse aesthetic, all just moments from downtown Mill Valley, award-winning schools, and premier outdoor access.