California Code, Streets and Highways Code - SHC § 128

The department shall maintain, in each district office, a file of its final construction plans and right-of-way record maps for all completed state highway projects located within the district.  The department may file, in the office of the recorder of the county in which any state highway is located, such plans, maps, or drawings of each state highway as the department deems necessary in the public interest, which the county recorder shall accept and file without fee.  No certificate need be attached thereto other than the usual title of the department showing the approval of such plans, maps, or drawings by the proper officer or engineer of the department.

All maps filed in the office of a county recorder pursuant to this section shall conform to the provisions of this paragraph.  The map shall be legibly drawn, printed, or reproduced by a process that provides a permanent record.  Each sheet of paper or other material used for such map shall be 22 by 36 inches in size, shall have clearly shown therein the particular number of the sheet, the total number of sheets comprising the map, and its relation to each adjoining sheet, and shall have encompassing its border a line that leaves a blank margin one inch in width, except that the left side margin shall be two inches in width.  In any county using a microfilm system, such plans, maps, or drawings may be microfilmed in lieu of filing.