Abstract: A storage unit door locking system is shown for securing and locking a storage unit door and preventing forced entry wherein the door is attached to a doorjamb. The locking system has a door plate which is mounted to the door with an extension plate that extends beyond the edge of the door and abuts the front face of the doorjamb when the door is closed. A sliding bolt slidably mounted to, but spaced apart from, the door plate slides behind the doorjamb trapping the doorjambs between the extension plate and the sliding bolt. A recessed lock is inserted through matching aligned holes in the extension plate, doorjamb, and sliding bolt and locked. This physically locks the doorjamb to the extension plate and sliding bolt which prevents forced entry with the use of crowbars or other prying devices normally used to separate the doorjamb from the door and locks contained thereon.