California Code, Government Code - GOV § 23681

A petition praying for the submission of the question of the removal of the county seat, signed by a majority of the qualified electors of any county, as determined by the number of votes cast at the preceding general election, may be presented to the board of supervisors. Upon the filing of such petition, the board shall, by due proclamation, submit the question of removal to the qualified electors of the county at the next general election.