Welcome to 1477 Old Mill Road, a distinguished estate in the heart of San Marino. Nestled on an expansive 35,721 sq. ft. lot, this 5-bedroom, 6-bathroom Colonial style home seamlessly blends historic charm with modern luxury. Originally built in 1923 as one of the model homes for the prestigious Oak Knoll Marino subdivision, the property retains its original architectural beauty with thoughtful expansions and updates for contemporary living. Upon entering the home, a sophisticated formal living room centers on a fireplace, built-in bookshelves and french doors opening out to a covered patio. The adjacent sunroom, bathed in natural light, serves as a fantastic office area or cozy retreat. The large formal dining room is ideal for hosting, while the open kitchen and family room offer a beautiful expansive space for more casual gatherings with family and friends. The chef's kitchen features marble countertops and a suite of top line appliances including two glass-front Sub-Zero refrigerators, a Viking range with dual ovens, an additional Viking wall oven and warming drawer, built in microwave, Miele coffee maker and steam oven and custom cabinetry with substantial storage. The large center island offers additional prep and dining space, making it both beautiful and functional, the centerpiece of the kitchen, A large butlers pantry features additional storage for glassware and dishes, two wine refrigerators and a warming drawer. Upstairs, the ideal floor plan unfolds. The private primary suite is a true retreat, boasting enormous vaulted ceilings, two balconies, an oversized dressing room and closet plus the primary bathroom with dual sinks, marble countertops, and an elegant bathtub. One of the three additional upstairs bedrooms enjoys its own en-suite bathroom, while the remaining two charming bedrooms share a well-appointed Jack-and-Jill bath. Beyond the main residence, the detached guest house provides total privacy for guests with a living room with vaulted ceilings, a full bedroom suite, and private garden. The park-like grounds feature a pool with a spa, a large grass expanse, a pretty outdoor dining pavilion covered in trumpet vine, and a barbecue area. A three-car garage completes this spectacular estate. Located within the award-winning San Marino Unified School District and moments from The Huntington Library, Lacy Park, and Mission Street's boutiques and dining, this estate offers a rare opportunity to own a piece of San Marino's rich history.