Juan Maria Osuna was granted the land that is now San Dieguito County Park by the Mexican government in 1840. He built an adobe home for his wife and 14 children and used the acreage for farming and livestock. Osuna’s legacy became a lush oasis for Solana Beach, Del Mar and Rancho Santa Fe.
In 1906, Juan Osuna’s heirs sold the family’s property to a subsidiary of the Santa Fe Railway, which planted 3.5 million Eucalyptus seeds in hopes of using the wood for railroad ties. When that didn’t work out, the company sold individual parcels that eventually helped create the town of Rancho Santa Fe. Eventually, the land the park now occupies was owned by the Santa Fe Irrigation District (SFID).
In 1952, H.G. Larrick Sr., then president of the irrigation district, floated the idea of creating a park. Don Armstrong, a Solana Lumber sales executive, promoted the notion with the San Dieguito Junior Chamber of Commerce, which agreed to sponsor the project. Armstrong initially envisioned a small park of, say, five acres, to be carved out of what was — even then — the most expensive land in San Diego county, selling for $5,000 an acre or more. But Larrick and the SFID Board of Directors had a grander vision. “I was thinking of a larger park. I have a site in mind that would be closer to 100 acres,” Larrick told Armstrong and his fellow Jaycees.
Many, many meetings later, the SFID directors and County Board of Supervisors came to agreement on deeding the park land to the County of San Diego. The year was 1954. The cost? A symbolic $10 check, hand-drawn extra-large for a triumphant photo-op. But those were the days of big strobe “flash” lighting and — twice — the newsman’s flash failed.
[Source: 40 Years of Progress: 1922 to 1962, San Dieguito Citizen]