Rancho San Mateo was a 6,439-acre (26.06 km2)Mexican land grant on theSan Francisco Peninsula, in present daySan Mateo County, California.
It was given in 1846 by GovernorPio Pico to Cayetano Arenas.[1]
Rancho San Mateo extended from the foothills of theSanta Cruz Mountains toSan Francisco Bay. It includedCoyote Point, about one-half the present city ofSan Mateo, all ofBurlingame and most ofHillsborough.[2]


Pio Pico, the last governor of California under Mexican rule, made the grant to his secretary, Cayetano Arenas of thePueblo de Los Ángeles, for his family’s service to the government. Cayetano Arenas father wasLuis Arenas.
Arenas sold the property in 1846 toYerba Buena (Pueblo de San Francisco) merchant and American immigrantWilliam Davis Merry Howard. Howard with his wife, Agnes, retired from the city to live on the rancho in 1854, and built a residence named "El Cerrito" and developed a successful working ranch.
With thecession of California to the United States following theMexican-American War, the 1848Treaty of Guadalupe Hidalgo provided that the land grants would be honored. As required by the Land Act of 1851, a claim for Rancho San Mateo was filed with thePublic Land Commission in 1852,[3][4] and the grant waspatented to William Davis Merry Howard in 1857.[5] A claim byJosé de la Cruz Sánchez was rejected.[6]
Howard's early death in 1856 at the age of thirty-seven led to the sale of most of the land toWilliam C. Ralston, a prominent banker.
In 1861, Henry F. Teschemacher and Joseph P. Thompson were opposed in an important court case concerning the Rancho San Mateo patent and land under water at high tide.[7]
In 1866,Anson Burlingame, theUS Minister to China visited Ralston, and by the time he left he was the owner of 1,043 acres (4 km2) of land. His name “Burlingame” was put onto the parcel map for reference. That visit to the San Francisco Peninsula, was Burlingame’s last. On a visit to Russia in 1870, Burlingame died. With his death the land reverted to Ralston. Ralston had plans for the area which he called “Ralstonville”, but he died in 1875 without many of his plans being realized.
The land passed to Ralston's business partner SenatorWilliam Sharon. Sharon died in 1885, and Sharon's son-in-law,Francis G. Newlands, became executor of Sharon’s estate.[8]
37°34′48″N122°19′48″W / 37.580°N 122.330°W /37.580; -122.330