Ready to build! Nestled in the heart of San Marinos most prestigious and established estate enclave, Oak Knoll Avenue presents a rare and extraordinary opportunity to secure one of the finest legacy residential parcels in the area. Located just moments from the iconic Langham Hotel and a short stroll to the beloved Lacy Park, this nearly 31,000 square foot flat lot offers unmatched privacy, scale, and development potential in one of Southern Californias most highly regarded neighborhoods. The property is offered primarily for land value, providing an exceptional canvas for the creation of a world class custom residence. The existing home is planned to be removed, and the sale includes fully developed and submitted architectural plans for an elegant 5,935 square foot two story Spanish inspired luxury estate with a three car garage. This design concept embraces timeless architectural character, refined indoor outdoor living, and modern lifestyle functionalityperfectly aligned with the areas historic charm and luxury standards. With a wide frontage, generous setbacks, mature trees, and expansive grounds, the site affords both privacy and presence, offering the flexibility to create a resort like environment with pool, gardens, and multiple outdoor entertainment zones. The parcels impressive lot size also presents potential for additional improvements, including an ADU or guest casita, subject to city approvalfurther enhancing the long term value and versatility of the site. Located within the boundaries of the award winning San Marino School District and surrounded by many of the citys most iconic estates, this address is synonymous with enduring prestige, architectural excellence, and generational value. Opportunities to acquire large, build ready estate parcels in this prime heritage zone are exceedingly limited, particularly those accompanied by pre planned luxury home designs that honor the neighborhoods character while meeting modern standards of scale, livability, and privacy. A rare blend of location, scale, architectural vision, and development readiness, this estate caliber parcel invites its next steward to bring a dream home to life in one of the most distinguished pockets of San Marino.