In the physical domain, the military key terrain is any locality, or area, the seizure or retention of which affords a marked advantage to either combatant (DOD Joint Staff 2016). In the physical domain, the commander has responsibility for a specific geographic boundary and his assets are typically within that boundary. In the cyber domain, information assets spread across the globe with data that moves between shore, afloat and air platforms following a complex set of interconnected links that vary between platforms, data sets and geographic locations. This complex interconnected set of information assets that are required to execute a mission or prevent an adversary from executing its mission is the cyber terrain. The challenge for cyber is the ability to understand what constitutes the cyber key terrain, as it does not follow geographic boundaries.