Rancho Blucher was a 26,759-acre (108.29 km2) Mexican land grant in present day Marin and Sonoma County, California given in 1844 by Governor Manuel Micheltorena to Jean Jacques Vioget.
[1] The rancho is named for the Prussian field marshal Gebhard Leberecht von Blücher.
After applying to Governor Juan B. Alvarado for a tract of land in northern Marin, Vioget received a provisional grant in 1842.
Governor Micheltorena awarded Vioget full rights to Rancho Blucher in 1844.
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.