On October 24, 1849, Governor Bennet C. Riley, the military governor of California, issued a proclamation designating Thursday, November 29th, as a day of thanksgiving.
In conformity with the customs of other states and territories, and in order that the people of California may make general and public acknowledgement of their gratitude to the Supreme Ruler of the Universe for his kind and [?] care during the past year, and for the boundless blessings which we now enjoy, it is recommended that Thursday, the 29th day of November next, be set apart as a day of Thanksgiving and Prayer.
Given at Monterey, California, this 24th day of October, A.D. 1849. (Signed) B. Riley. Bvt. Brig. Gen. U.S.A. and Governor of California
How was that first Thanksgiving Day celebrated? That’s hard to know. I can’t find any extant newspaper articles or letters.
In 1849 Thanksgiving Day was not yet a national holiday. That wouldn’t happen until 1863, when President Abraham Lincoln called for a national day of “Thanksgiving and Praise.” Up until then, the holiday was left to individual states.
As the San Francisco Call noted, it was a holiday mainly associated with New England, and men from those states would have marked the day, perhaps with an especially good meal of game or delicacies from the nearest trading post.
For men who remembered a bountiful meal at a family gathering, it must have also been a day of homesickness and longing.