Whenever a county or city and county owns land in another county, it may request the sheriff of that county to deputize its officers or employees as deputy sheriffs so that they may perform police duties solely upon said land. The sheriff may appoint such deputies.
Source:
Section 26608.2, https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?lawCode=GOV§ionNum=26608.2..