Espionage & Censorship Act 18 USC Sec. 795
It is this section of the Internal Security Act that allows Area 51 border security, known as the cammo dudes, to keep you out of Groom Lake–and use deadly force if necessary.
The basic gist of this law is that you cannot cross the border into Area 51. If you do, they will detail you until the Lincoln County Sheriff’s department arrests you and takes you to jail. While they can fine up to $5000 and one year in jail, or both, if they find that you have accidentally crossed the border, they will likely just give you a $650 fine and send you packing.