The Tannen residence at 1809 Mason Street in Hill Valley was the 1955 home to Biff Tannen and his grandmother Gertrude Tannen. Mrs. Tannen's name was displayed on a sign hanging over the front door. The house had an adjoining garage, where Biff parked his Ford Super De Luxe Convertible when he was at home. It does not appear that the Tannen family encouraged visitors, judging by the large handwritten sign at the gate reading NO TRESPASSING! / VIOLATORS WILL BE PROSECUTED / THIS MEANS YOU!! A post bearing a handwritten KEEP OFF THE GRASS! sign was also stuck into the lawn.