Previous: A-43: Avenues of Approach
A-47. Key terrain is locations or areas whose seizure, retention, or control gives a marked advantage to either combatant. It is a conclusion, usually arrived at after enemy analysis and COA development, rather than an observation.
A-48. A prominent hilltop overlooking an avenue of approach might or might not be key terrain. Even if it offers clear observation and fields of fire, it offers nothing if the enemy can easily bypass it, or if the selected course of action involves maneuver on a different avenue of approach. However, if it offers cover and concealment, observation, and good fields of fire on multiple avenues of approach, or on the only avenue of approach, then it offers a definite advantage to whoever controls it.
A-49. The leader must assess what terrain is essential to mission accomplishment. Another example of essential terrain for a platoon and squad in the attack is high ground overlooking the enemy’s reverse-slope defense. Controlling this area could prove critical in establishing a support-by-fire position to protect a breach force.
A-50. Decisive terrain. Leaders also must determine if terrain is decisive. This is key terrain which seizure, retention, or control is necessary for mission accomplishment. Some situations have no decisive terrain. If a leader identifies terrain as decisive, this means he recognizes seizing or retaining it is necessary to accomplish the mission.
A-51. Tactical considerations in analyzing key terrain. Terrain is important for friendly observation, both for commanding and controlling and for calling for fire? What terrain is important to the enemy and why? Is it important to me? What terrain has higher headquarters named as key? Is this terrain also important to the enemy? Is the enemy controlling this key terrain? How do I gain or maintain control of key terrain? What terrain is essential for communications nodes dictating the employment of digital communications equipment?