Harbor Oil Refining Company Gas Station Road Maps of California
Harbor Refining Company - California Road Maps
Harbor Refining Company - California Road Maps - Front
Harbor Refining Company - California Road Maps - Back
I really don't know how many different years Harbor Refining produced maps, but the above is a good representation of their maps. The map in the bottom row appears to be from the 1920's. See the Harbor-CA-Spreadsheet for map code details