Rancho Agua Puerca y las Trancas was a 4,421-acre (17.89 km2) Mexican land grant in present-day Santa Cruz County, California given in 1843 by Governor Manuel Micheltorena to Ramón Rodríguez and Francisco Alviso.
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.
[7] In 1846 Felipe Armas (1809–) married Maria Antonia Rodriguez, sister of Ramón Rodríguez.
Marriage into this family enabled Felipe Armas to purchase Francisco Alviso's half of Rancho Agua Puerca y las Trancas in 1847.
[8] The Swanton Pacific Ranch comprises much of the original Rancho Agua Puerca y Las Trancas.