The Lighthouse was shot on location at Cape Lookout, NC and Atlantic Beach, NC. The lighthouse shown is the Cape Lookout Lighthouse.
During production on location at Atlantic Beach, NC, a Atlantic Beach policeman was on set the entire shoot. He acted as armorer and technical consultant for the handguns used.
The hand guns were real.
Justin Yates fell backwards into a pool of water dug for him in one shot. There were no other set of clothes to wear. It was the last shot of the day.
There was a crowd of residents onlooking the shoot. They were anticipating the gunshot scene where Justin falls backward. When it happened, one resident did a double take and then fled the set saying it looked to realistic.