Rancho Los Medanos

Rancho Los Medanos (from the Spanish: Rancho Los Médanos meaning Sand Dunes Ranch) was a 8,859-acre (35.85 km2) Mexican land grant in present-day Contra Costa County, California given in 1839 by Governor Juan Alvarado to Jose Antonio Mesa and Jose Miguel Garcia.

The name "los medanos" is derived from the sand hills located along the San Joaquin River on its northern boundary.

[3] 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.

[6] A claim for Rancho Los Medanos filed in 1853 by James Enright, Michael Murphy, and Ellen Fallon, was rejected.

[7] Colonel Jonathan Drake Stevenson (1800–1894) was the commanding officer of the 1st Regiment of New York Volunteers, part of the American occupation army force that landed in California in 1847.