Cal. Elec. Code § 12225

Whenever a precinct is entirely owned or controlled by the United States, and no permission is granted by the federal authorities for the establishment of precinct boards and polling places, precinct boards need not be appointed nor polling places designated, but in lieu thereof the elections official shall, not less than 88 days prior to election day, establish the precinct as a mail ballot precinct and conduct the election for that precinct in accordance with Section 3005.