Point Conception Lighthouse
The lighthouse used in the movie is actually the Point Conception Lighthouse. Point Conception is the least accessible lighthouse in the Coast Guard inventory and only visited by appointment. Google maps has a nice aerial photo that can be zoomed. There are also several sites with nice photos. The remote location and spooky pictures I have seen taken from the sea side intrigued me so I located all the info I could find. I wound up with 2 Scaasis resin lighthouse models and a resin model kit of the monster standing on a rock holding a head. I also located a 16MM film print.
I wonder if the title came before the location because Piedras Blancas Lighthouse also exists. Maybe had the location dictated the title it would be Monster of Point Conception which doesn't sound too bad.