California Government Code Section 23600 - Location of County Seats
The county seats of the respective counties of the state, as
fixed by law and designated in this article, are declared to be the
county seats of the respective counties. In any case where a county
seat is an incorporated city, it includes all territory heretofore or
hereafter annexed to the incorporated city.
The board of supervisors shall designate by resolution an
alternative temporary county seat, which may be outside the
boundaries of the county, for use in the event of war or enemy-caused
disaster, or the imminence thereof, but real property outside the
boundaries of the county shall not be purchased by a county for use
as a temporary county seat. A copy of the resolution shall be filed
with the appropriate county officials in that county and the
alternative county. A different temporary county seat may be so
designated at any time as circumstances indicate the desirability of
such a change.
The board, and any county officer or agency as directed by the
board, shall provide such facilities of any kind at the temporary
county seat as appear desirable for the functioning of the government
of the county at the temporary county seat in the event that it
becomes necessary, pursuant to this section.