An Advantage of terrain occurs when military personnel gain an advantage over an enemy utilizing, or simply in spite of, the terrain

Terrain

Terrain, or land relief, is the vertical and horizontal dimension of land surface. When relief is described underwater, the term bathymetry is used...

 around them. The term does not exclusively apply to battles, and can be used more generally regarding entire campaigns

Military campaign

In the military sciences, the term military campaign applies to large scale, long duration, significant military strategy plan incorporating a series of inter-related military operations or battles forming a distinct part of a larger conflict often called a war...

 or theaters of war

Theater (warfare)

In warfare, a theater, is defined as an area or place within which important military events occur or are progressing. The entirety of the air, land, and sea area that is or that may potentially become involved in war operations....

.

Mountains, for example, can block off certain areas, making it unnecessary to station troops within the inaccessible area. This deployment strategy can be applied with other formidable environmental features as well, such as forests and cliffs. In the former instance, dense vegetation can provide concealment for tactical movements such as setting up an ambush

Ambush

An ambush is a long-established military tactic, in which the aggressors take advantage of concealment and the element of surprise to attack an unsuspecting enemy from concealed positions, such as among dense underbrush or behind hilltops...

. In the latter, the elevation can provide an advantage to soldiers using projectile weapons, such as arrow

Arrow

An arrow is a shafted projectile that is shot with a bow. It predates recorded history and is common to most cultures.An arrow usually consists of a shaft with an arrowhead attached to the front end, with fletchings and a nock at the other.- History:...

s or artillery pieces. Elevation itself is perhaps the most well-known example of terrain advantage, with gravity working to the advantage of the more elevated party.

While securing a terrain advantage is an important consideration for a modern commander, particularly those engaged in unconventional tactics

Unconventional warfare

Unconventional warfare is the opposite of conventional warfare. Where conventional warfare is used to reduce an opponent's military capability, unconventional warfare is an attempt to achieve military victory through acquiescence, capitulation, or clandestine support for one side of an existing...

 such as guerrilla warfare

Guerrilla warfare

Guerrilla warfare is a form of irregular warfare and refers to conflicts in which a small group of combatants including, but not limited to, armed civilians use military tactics, such as ambushes, sabotage, raids, the element of surprise, and extraordinary mobility to harass a larger and...

. It was undoubtedly of even greater concern for pre-industrial forces, as lack of mobility and first generation warfare

First generation warfare

First generation warfare is a term created by the U.S. military in 1989, referring to the earliest stages of organized, state-controlled armed forces waging war in the modern era....

 left soldiers very vulnerable to its effects. The ancient military strategist Sun-Tzu, for example, dedicated an entire chapter in his influential treatise The Art of War

The Art of War

The Art of War is an ancient Chinese military treatise that is attributed to Sun Tzu , a high ranking military general and strategist during the late Spring and Autumn period...

to terrain and situational positioning.

Examples

• The Battle of Agincourt
  Battle of Agincourt
  The Battle of Agincourt was a major English victory against a numerically superior French army in the Hundred Years' War. The battle occurred on Friday, 25 October 1415 , near modern-day Azincourt, in northern France...
  
  - The nearby trees created a choke point
  Choke point
  In military strategy, a choke point is a geographical feature on land such as a valley, defile or a bridge, or at sea such as a strait which an armed force is forced to pass, sometimes on a substantially narrower front, and therefore greatly decreasing its combat power, in order to reach its...
  
   where the French were hit by English long bowmen. The main environmental factor in English victory was the extremely muddy area. The field had recently been plowed, and it had been raining recently.
• The Invasion of Normandy- The allies deployed soldiers in transports directly to Normandy Beach, where German Forces had heavily defended the area. At some portions of Normandy, cliffs bordered the beaches and allied troops were fired upon from above. Overall, the beach made it harder for Allied forces to take Normandy.
• The Alps
  Alps
  The Alps is one of the great mountain range systems of Europe, stretching from Austria and Slovenia in the east through Italy, Switzerland, Liechtenstein and Germany to France in the west....
  
   have long been used to protect northern Italy. Few people have tried crossing the alps in a military invasion, with some notable exceptions, (Hannibal Barca
  Hannibal Barca
  Hannibal, son of Hamilcar Barca Hannibal's date of death is most commonly given as 183 BC, but there is a possibility it could have taken place in 182 BC. was a Carthaginian military commander and tactician. He is generally considered one of the greatest military commanders in history...
  
   and Napoleon Bonaparte).
• The Himalaya Mountains have been used similarly.
• During the American Revolutionary war
  American Revolutionary War
  The American Revolutionary War , the American War of Independence, or simply the Revolutionary War, began as a war between the Kingdom of Great Britain and thirteen British colonies in North America, and ended in a global war between several European great powers.The war was the result of the...
  
  , Peninsular War
  Peninsular War
  The Peninsular War was a war between France and the allied powers of Spain, the United Kingdom, and Portugal for control of the Iberian Peninsula during the Napoleonic Wars. The war began when French and Spanish armies crossed Spain and invaded Portugal in 1807. Then, in 1808, France turned on its...
  
  , Vietnam War
  Vietnam War
  The Vietnam War was a Cold War-era military conflict that occurred in Vietnam, Laos, and Cambodia from 1 November 1955 to the fall of Saigon on 30 April 1975. This war followed the First Indochina War and was fought between North Vietnam, supported by its communist allies, and the government of...
  
  , etc., militants relied on the terrain to combat forces that were superior, either in numbers, or in quality.