The beautiful undulating land that Rancho Santa Fe now rests upon originally held local Kumeyaay Indian communities. Although, within the last two centuries it was under the jurisdiction of three successive governments, Spain, Mexico, and the United States of America. During the Spanish colonial period, Rancho San Dieguito was given ‘pueblo’ status by Spain because of the population of its native peoples. After Spain enacted the 1830 Act of Secularization the Mexican Republic era came to power, albeit for just a few decades before California statehood in 1850.

In 1831 Librado Silvas obtained a portion of Rancho San Dieguito under a provisional grant issued by Mexican Governor Manual Victoria. After Victoria’s overthrow, Juan Maria Osuna received permission from Governor Jose M. Echeandia to occupy the land and he took possession of it in 1836 for a future family home and ranch.

Osuna was born in 1785 and raised at El Presidio Reál de San Diego. His father was a corporal in the Soldados de Cuera (Leather Jacket Company), who escorted Father Serra and his entourage into Alta California at the onset of the Spanish Colonial period. Osuna worked his way up the military ranks and in 1834 the Mexican period San Diego held its first election. Juan Osuna was elected Alcalde or mayor.

Osuna was the first military man to leave the Presidio and began ranching. He chose the property he had trekked across many times as a soldier between Mission D’Alcala and Mission San Luis Rey. In 1840 or 1841, Governor Juan B. Alvarado gave him a provisional land grant, and finally, in 1845 Governor Pio Pico awarded him full title to the two square leagues of land (8,8224.71 acres) that comprised the entire Rancho San Dieguito.

While Osuna preferred to live in San Diego he built an adobe ranch house at Rancho San Dieguito for himself and his wife Juliana, known today as Osuna 2, (privately owned). He left the duties of managing the ranch to his son Leandro, to whom he gave the existing Silvas adobe, commonly referred to as Osuna 1. Although a fine Alcalde Osuna was also a gambling man, and lost some of his land to pay off bad debts.

Upon his father’s death in 1851, Leandro took possession of the land. A veteran of the Battle of San Pasqual in 1846, Leandro was a man of erratic temperament. His cruel treatment of the Indians led to his demise in 1859. Tiring of this harsh treatment, it was rumored the Indians poisoned Leandro and then told him of his impending agony. Rather than face a slow, painful death, he committed suicide, leaving the care of Rancho San Dieguito entirely in the hands of his mother, Juliana, Juan Osuna’s widow. By 1875, only a small portion of the land remained in the possession of the Osuna family. The last parcel under their ownership, 116 acres, was sold in 1906.