The San Dieguito Community Plan Area is, generally, a low-density estate residential area surrounded by the rapidly urbanizing areas of North San Diego County. To the west lie the coastal cities of Encinitas and Solana Beach; to the north are Carlsbad and San Marcos; to the east Escondido; and on the south, the City of San Diego.
The San Dieguito Plan Area was first inhabited by Indians, and evidence indicates that a large thriving aboriginal population lived throughout the Plan Area. During the period of Spanish colonization the area was used as rangeland. Following the Mexican Revolution of 1822, land known as Rancho San Dieguito was given to Juan Osuna who settled within the area of what is now the community of Rancho Santa Fe.
In the early Twentieth Century, most of the land that comprised Rancho Santa Fe was sold to the Santa Fe Land Development Company. The company wanted to use the land to grow trees that could be harvested, primarily, for railroad ties. However, an unfortunate choice was made to plant about three million eucalyptus trees which proved to be useless as lumber. While this venture was a failure, the trees thrived in the climate, and the man-made forest was to become an important element in marketing the land for large-lot estate residential development.
-San Dieguito Community Plan, San Diego County General Plan