Until President Abraham Lincoln proclaimed a national day of thanksgiving during the Civil War, thanksgiving holidays were a matter of state and local concern.   California mentions Thanksgiving Day in 18 separate statutes, including those in the Code of Civil Procedure, Civil Code, and even the Fish & Game Code.  The last statute, however, has nothing to do with turkeys.  Rather, Fish & Game Code Section 5523 concerns the timing of the opening of the Dungeness crab season.

California may have more than one day of thanksgiving.  Government Code Section 19853 provides that all state employees are entitled to various specified holidays, including  every day appointed by the Governor of this state for a public fast, thanksgiving, or holiday.

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