(a)
Except as provided in subdivision (b), the proceeding shall be commenced in the county in which the property sought to be taken is located.(b)
When property sought to be taken is situated in more than one county, the plaintiff may commence the proceeding in any one of such counties.
Source:
Section 1250.020, https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?lawCode=CCP§ionNum=1250.020..