mill site

A parcel of land on or contiguous to a watercourse, suitable for the erection and operation of a mill operated by the power furnished by the stream.

Specifically, in mining law, a parcel of land constituting a portion of the public domain, located and claimed by the owner of a mining claim under the laws of the United States (or purchased by him from the government and patented), not exceeding five acres in extent, not including any mineral land, not contiguous to the vein or lode, and occupied and used for the purpose of a mill or for other uses directly connected with the operation of the mine; or a similar parcel of land located and actually used for the purpose of a mill or reduction plant, but not by the owner of an existing mine nor in connection with any particular mining claim.

See 30 U.S.C.A. No. 42