The California State Census taken in 1852 just went live on Ancestry.com. So, of course, I had to see if there were any Greeks listed.
There were 14 people listed with Greece as their place of birth. This was during the Gold Rush in California, not suprising, 10 of the 14 people were men listed as Miner's in Calaveras and Placer Counties in California (hotspots of the Gold Rush). There were also 2 females listed in San Francisco, 1 in Sacramento and 1 in Shasta, California.
Name - County - Approx Birth Date - Occupation
Nichls - Calaveras - 1822 - Miner
M. Reese - Calaveras - 1808 - Miner
Richard Webb - Calaveras - 1818 - Miner
Coralmabe - Placer - 1830 - Miner
John Brobins - Placer - 1812 - Miner
John Casteline - Placer - 1810 - Miner
John Cecil - Placer - 1830 - Miner
Bootool Jeards - Placer - 1822 - Miner
George Nichols - Placer - 1820 - Miner
George Williams - Placer - 1828 - Miner
Isabella Benn - San Francisco - 1812 - No occupation listed
Narcissa Townsend - San Francisco - 1826 - No occupation listed
A. B. Tomlinson - Sacramento - 1816 - Hotel Keeper
Florina Mitchel - Shasta - 1818 - No occupation listed
You can view the actual 1852 California Census Records at Ancestry.com
Good luck with your Greek family history research.
Georgia Keilman nee Stryker (Stratigakos)