California Code, Public Resources Code - PRC § 3910

The proprietor of a vein or lode claim or mine, the proprietor of a placer claim, or the owner of a quartz mill or reduction works, or any person qualified by the laws of the United States may locate not more than five acres of nonmineral land as a millsite.

The location shall be made and the claim boundaries marked in the same manner as required by Section 3902 for locating placer claims, except that the monument in or on which the notice of location is posted may be erected anywhere within the claim, and location work is not required.