Originally part of the northern lands of Mission San Luis Obispo de Tolosa, the four square league Rancho Santa Margarita was granted to Estrada in 1841.
At the time, his older half brother Juan Bautista Alvarado was Governor of Alta California for independent México.
[4] With the Mexican Cession of California to the United States following the Mexican–American War, the 1848 Treaty of Guadalupe Hidalgo provided that the land grants would be honored.
In 1889, Patrick Murphy enticed the Southern Pacific Railroad to Rancho Santa Margarita by selling them land near the ranch house.
In 1904, the Murphy family sold Rancho Santa Margarita to the three Reis brothers – Ferdinand, Christian and Gustav, German emigrants who made their fortune in the California Gold Rush.