Military geography is a sub-field of geography that is used by the military, as well as academics and politicians, to understand the geopolitical sphere through the military lens. To accomplish these ends, military geographers consider topics from geopolitics to physical locations’ influences on military operations and the cultural and economic impacts of a military presence. On a tactical level, a military geographer might put together the terrain and the drainage system below the surface, so a unit is not at a disadvantage if the enemy uses the drainage system to ambush it, especially in urban warfare. On a strategic level, an emerging field of strategic and military geography seeks to understand the changing human and biophysical environments that alter the security and military domains. Climate change, for example, is adding and multiplying the complexity of military strategy, planning and training. Emerging responsibilities for the military to be involved in: protection of civilian populations (Responsibility to protect), women and ethnic groups; provision of humanitarian aid and disaster response (HADR); new technology and domains of training and operations, such as in cybergeography, make military geography a dynamic frontier.
If a general desired to be a successful actor in the great drama of war, his first duty is to study carefully the theater of operations so that he may see clearly the relative advantages and disadvantages it presents for himself and his enemies.
Military geography has a long and practical history. For example, Imperial Military Geography in 1938  shows how a colonial empire approach to military geography could describe the geographical setting of empire, the responsibilities and the resources that could be mobilised for national or imperial needs. Environmental determinism, regional geography, geographic information systems and geography more generally have all evolved and entwined over hundreds of years.
Canadian, South African and Australian military geography (Pearson et al. 2018) is inconspicuous compared to the United States and British traditions.
There are important links to peace studies and particularly notable was Australian Professor Griffith Taylor who espoused Geopacifics as, an attempt to base the teachings of freedom and humanity upon real geographical deductions; it is humanized Geopolitics  and later observed that, ...so few geographers are prepared to explore public problems which touch on geography as much as on most other disciplines. This is certainly the case with the problem of world peace. 
Russian colonel N. S. Olesik terms the field of analyzing the complex urban environment in particular “military geo-urbanistics.” In the open country, units only deal with terrain, weather, and the enemy. In urban warfare, the terrain is more complex, filled with many structures and transformations of the land by the inhabitants, which restrict visibility from the air and create obstacles to ground units. Spaces may be narrow, and convoys may be restricted to certain routes between buildings, where they face roadside bombs and ambushes.
Units must work with or work around local people, some of whom may cooperate and others of whom may oppose, while others are neutral or caught between the two factions. Guerilla fighters may count on an enemy's unwillingness to bomb or fire on heavily populated areas.
Several types of terrain and associated climate are prevalent, each affecting combatants differently.
Main article: Desert warfare
In an arid climate, as in many desert areas across the globe, sand is a main concern. Sand can hamper an army's attempts to remain hydrated, sapping moisture from skin; sand also jams machinery including the firing mechanisms of firearms.
Terrain is usually fairly flat, though in some regions there are vast, rolling sand dunes. The desert environment can also contain mountains; as in Afghanistan and in certain areas around Israel. Due to the ongoing conflicts in the Middle East, the U.S. military has redesigned the uniforms for the different branches of service. All of the uniforms have a digital camouflage pattern that is very effective in the desert environment, and the boots have been changed from the standard polished black boots to light brown colored suede leather boots. These boots are cooler under the intense heat of the desert sun.
Main article: Jungle warfare
The conditions of these regions are basically the opposite of those found in desert regions. There are thousands of flora and fauna, and there is always moisture present which presents its own difficulties. The moisture speeds up the rotting processes as well as causing wounds to become infected much easier because of all of the bacteria that live in the water. With proper filtration systems an army should have no problem keeping hydrated.
The densely packed trees and underbrush provide concealment from the air as well as from the ground. Ambushes can be easily conducted in this environment just like they can in an urban environment. The jungle can also contain mountains, but these mountains are organized differently from those that exist in the desert. The jungle mountains have far more plant life, and are usually much more difficult to ascend. Helicopters have been proven as a very useful means of transportation over jungle and forested areas; Vietnam was, of course, the testing ground for this. Tanks and other vehicles have difficulty maneuvering through and around the densely packed trees, and most military aircraft fly too fast to accurately observe the ground through the trees.
See also: Arctic warfare
This type of warfare is not based on a geographical design, but is based on the drastic differences in this particular climate. During war it is much harder to remain warm than it is to remain cool. Even Forested areas can, and many do, experience winter weather conditions. For this specific type of combat there are soldiers that are specifically trained to fight under the conditions individual to the winter season. These conditions call for a drastically thicker and thus warmer uniform, and the weapons even need to be refitted with the proper devices to ensure that they will operate in the cold.
Main article: Mountain warfare
No two mountains are alike, but there is less oxygen at higher altitude. Fighting up a mountain can be very treacherous. There can be avalanches, rockslides, cliffs, and ambushes from higher up the slopes, and there are almost guaranteed to be caves somewhere in the mountain, as in Afghanistan.
Mud is a universal menace to all armies. While it does not hamper the use of air power, it slows and sometimes stops ground movements all together. The most common season for mud across the globe is spring. After the thawing of winter's snow and the addition of the rains that the season brings, the ground becomes very soft, and almost any military vehicle can get bogged down if it is not properly equipped. The mud is not always dependent on the spring. Rather, in some parts of the world, it is determined by the monsoons.
Even today, there is still a problem of piracy on the world's oceans. One of the most commonly thought of areas for this criminal activity is off the coast of Somalia. There has always been the constant threat of small and fast attack craft coming out to greet a vessel as it passes through the waters between Africa and the Middle East. Another region that piracy occurs, and it can be of a much larger scale, is in and around the Indonesian islands and off the coasts of the Asian mainland. Here the pirates have been able to capture much larger prizes, and they pose a much larger threat to the security of economic interests of many countries. Pirates operate from bases that are concealed, but they must be on the waterfront in a country that is either ignorant of their activity, or worse, are paid to overlook it. To deal with the pirates, if an American vessel is attacked, the U.S. Navy has multiple assets to deal with the situation. If the pirates know an attack is imminent, it may be more logical to bomb their base with aircraft from one of the carriers. However, more often than not, the U.S. Navy would opt for secrecy and send in a smaller force, such as the U.S. Navy SEALS, to eliminate the threat.
In the concerns of a seaport, especially if it is a goal to either capture or defend it, there are more difficulties than in defending a city that is in land. With a harbor there is also the threat from the sea in addition to the land and the air. A harbor is always a key objective for an army to capture when an invasion is commenced. The sooner the harbor can be captured, the sooner it can be used to bring in massive amounts of reinforcements and material. The trouble is to capture the harbor before the enemy can sabotage it by blocking the entrance with wreckage or by deploying mines throughout the harbor. Defending the harbor is a treacherous task because odds are that the enemy can observe your position from both the air and the sea. The harbor is on the periphery of the defense network of many nations, and even more so if the navy is either deployed or nonexistent. The best ways to defend the harbor are to have military airfields in close vicinity, to have naval units based in the harbor on a permanent basis, and to be ready to make the harbor unusable by the enemy if they should overcome your defenses.
Beaches have always been a favourable place for landings. Beaches with naturally shallow inclines are often used for deploying troops and armoured vehicles. Often, however, they can be blocked by mines and other anti-tank defences. This makes them a high risk place to land but, if there is no prior warning, a beach-landing can be a very effective route into enemy territory.
The same rules apply to this category as to the preceding one with the exception of the mines. Here there is almost no need for anti-vehicle mines, and so, the defenses could be planned without much concern for an armored attack.
The Middle East contains numerous valuable resources that major nations may compete over when supplies begin to fall around the world. The first Gulf War was an example of the United States’ willingness to go to war to protect its access to the rich oilfields of the Persian Gulf. The strong military presence influenced some leaders to aid the United States with cheap oil, but over time those forces began to be viewed as a threat to the Muslim world. The attacks of September 11, 2001, have brought new hostilities to the region with the invasions of both Afghanistan and Iraq. Other hotspots around the globe centering on oil are the areas around Venezuela, the Caspian Sea region, and possibly the offshore oil deposits around Vietnam and China. In today's age, especially for people living in developed countries, it is hard to believe that there are other resources that can potentially cause a war.
The most precious and most needed resource of all is water, and in some parts of the world, that is a very expensive resource to obtain. The most obvious areas that conflict may arise over disputes for water supplies would be in the desert, but at the moment oil is the most valuable liquid in the Middle East. However, oil will not always be there, and if those people are going to survive, they must have water. Several times, countries that are upriver have threatened to build dams across the rivers in order to cut off the country down river, starving that particular country of its water supply. This has been the case with both the Nile and the River Jordan, and the results in both cases have been the same: the countries that are down river have threatened retaliation if such an event should occur. As our global warming trend continues, our weather patterns will continue to shift, and that means that some places will fall into a severe drought. These people may become desperate when they do not have the resources to obtain water if such a disaster should occur.
Water is not the only resource on this planet that is found to be a necessity. The forests are as well. These densely wooded regions of the world are constantly shrinking, and as the oil runs out, people will need to keep warm in the winter. Odds are that they will return to using wood as a primary fuel source for keeping warm. As the forests shrink, neighboring countries will turn on each other for this resource in order to appease their populations. The forests of Latin America and the Pacific Islands are the key hotspots for this resource; this is in part due to the already tense situations in and around those regions because of growing tensions over global oil supplies.
In 2002's Die Another Day, the term "conflict diamonds" is at the heart of the film's plot. In the film, the diamonds are the currency that is used to fund illegal weapons deals, and are used to fund the construction of the Icarus space weapon. The portrayal of the use of the diamonds that come out of Africa holds true in many cases. The term “conflict diamonds” is applied to those diamonds that are not sold through an internationally recognized company. They are “conflict diamonds” because warlords in Africa fight for these diamonds in order to sell them to acquire larger wealth and new weapons for continued fighting. The same is true for the gold fields in southern Africa. There are many warlords that would love to have control of the vast wealth of the mines in order to further fund their lucrative endeavors.
The United States Department of Defense maintains a larger number of domestic and foreign military bases than all other countries combined. Closing redundant military bases in the United States often has a negative economic impact on local communities. Analysts at the Pentagon respond to budget limitations by identifying installations that have become obsolete for various reasons. Sometimes the needs for the location are no longer prevalent in defense strategies or the installation's facilities have fallen into disrepair. That is the case with the smaller Reserve and National Guard facilities that dot every state. The personnel on the committees responsible for determining closures also observe the economic impact that their decisions will have on the communities surrounding the installations. If 40,000 people are employed because of the installation, either directly or indirectly, it is more likely that that facility will remain open, but only if there is nowhere for the 40,000 people that would lose their jobs. Those people could end up on welfare, thus becoming just as much of a draw on revenue as they were as employees.
Outside of the United States, some countries are strongly vying for inclusion in strategic treaties such as NATO. These countries, many of which are in Eastern Europe, want to join NATO for the mutual advantages of defense and the possibility for foreign bases to be constructed on their soil. These bases, if they were to be built, would bring fiscal resources that those nations would not get without the bases. Sometimes foreign bases are viewed as a good thing. In other regions, a strong political stance may be taken against the construction of foreign military bases, often for sovereignty issues.
Due to the subfield of military geography's perceived connection to traditional or classical geopolitics, a field which has since the end of the Cold War been largely rejected as a research focus by proponents of the popular schools of both critical geography and Marxist or radical geography, military geography has experienced a decline in popularity in academic circles. This is true particularly in institutions unaffiliated with or unconnected to military or governmental organizations. As a result, although there do exist some popular nonfiction writers of geography without academic credentials in the field who touch on military strategy or tactics, there are presently few practicing military geographers or students of military geography in academia. Similarly, there have been few major texts on military geography published specifically for a civilian academic audience since the early 2000s. More recently, in a 2014 article published in the journal Critical Military Studies, the authors Rech et al. suggest a revival of the field in line with critical geography and critical geopolitics. One earlier example of this school of thought has been Woodward's 2004 text Military Geographies. However, given the postmodern bias of critical geographical studies as well as critical geography academics' tendency to proudly claim for themselves a politically radical or anti-authoritarian slant in their research, this form of a revival of military geography seems unlikely to provide sound recommendations for or detailed analyses of major geopolitical events. This shift in focus would also make military geography less likely to fruitfully inform governmental policy or military strategy, as well as potentially limit the ability of academics to provide their expertise to members of the general public interested in studying or reading about the geographic aspects of military strategy.
The revival of geography and military geography as a sub-discipline is a remarkable trend since 2000 with a number of key geopolitical, international relations, historical geography  and geographical approaches being developed. The American Association of Geographers and Institute of Australian Geographers have interest groups that continue to develop the sub-discipline of military geography. At the American Association of Geographers meeting in 2018 a committee gathered evidence about militarism and military geography.
In 2018, Australian Contributions to Strategic and Military Geography  outlined a new Australian approach and included chapters on themes and specific regions.