I Am Number Four Wiki

The safehouse used by Mark James, provided for by GUARD. It was destroyed by GUARD shortly after the Mogadorians discovered and raided the ranch. Sarah, Mark, and BK had to fight their way out. 

Yellowhammer Ranch was the first major safehouse GUARD had, after being on the move for several years. It was littered with sophisticated traps, doors, and security systems. It was built and designed to be a safehouse for the Loric Garde in the future. GUARD left the ranch due to it feeling too safe and made way for her new and current base of operations, the Pecan farm.

The ranch was later discovered by the Mogadorians, after Mark revealed his location (accidentally).He and Sarah were caught by surprise as the traps were not re-activated, causing the immediate destruction of the ranch,so all the Loric information would not be captured by the Mogardorians.

The ranch's security:

A bomb, capable of blowing up the house and all its content (for Loric security).

Automatic weapons, if activated.

Several trip wires, offering a early warning system.

A full perimeter of cameras, offering 24/7 live feeds.