Pedro Pascual Estrada (1822–1897), son of José Raimundo Estrada and Josefa Vallejo de Alvarado, was born in Monterey. Pedro Estrada was granted Rancho Asuncion, originally part of the Mission San Luis Obispo de Tolosa, in 1845. His brother Joaquín Tomas Estrada was granted the adjacent Rancho Santa Margarita in 1841.
With the 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. As required by the Land Act of 1851, a claim for Rancho Asuncion was filed with the Public Land Commission in 1853, and the grant was patented to Pedro Estrada in 1866.
Pedro Estrada sold the rancho in 1861 to Martin Murphy Jr. (1807–1884) and his wife Mary Bulger Murphy (d.1892) of Sunnyvale, who had come to California with the Stephens-Townsend-Murphy Party in 1844. The Murphys turned over running of the rancho to their son Patrick Murphy, who was a General in the California National Guard. Patrick Washington Murphy (1840–1901) operated Rancho Asuncion, and the adjacent Rancho Atascadero, and Rancho Santa Margarita, altogether comprising about 61,000 acres (247 km2), from his Rancho Santa Margarita headquarters.
- Ogden Hoffman, 1862, Reports of Land Cases Determined in the United States District Court for the Northern District of California, Numa Hubert, San Francisco
- Diseño del Rancho Asuncion
- U.S. Geological Survey Geographic Names Information System: Rancho Asuncion
- Hoover, Mildred B.; Rensch, Hero; Rensch, Ethel; Abeloe, William N. (1966). Historic Spots in California. Stanford University Press. ISBN 978-0-8047-4482-9.
- United States. District Court (California : Southern District) Land Case 76 SD
- Report of the Surveyor General 1844 - 1886
- J. P. Munro-Fraser, 1881, History of Santa Clara County, California, Alley, Bowen & Co, San Francisco
- Biography of Martin Murphy, Jr.
- Thompson & West , 1883, History of San Luis Obispo County California, Oakland
- Patrick Washington Murphy