Home guard is a title given to various military organizations at various times, with the implication of an emergency or reserve force raised for local defense.
The term "home guard" was first officially used in the American Civil War, starting with units formed by German immigrants in Missouri, and may derive from possible historical use of the term Heimwehr ("home guard") to describe units officially known as Landwehr ("country guard"), or from an attempted translation of landwehr.
| Country | Name | Active | |
|---|---|---|---|
 |  Sweden | Swedish Home Guard | 1940– |
 |  Norway | Norwegian Home Guard | 1946– |
 |  Denmark | Danish Home Guard | 1949– |
 |  Estonia | Estonian Defence League | 1918–1940, 1990– |
 |  Germany | Heimatschutz of Bundeswehr | 1965–2007, 2019– |
 |  Latvia | Latvian National Guard | 1991– |
 |  Lithuania | Lithuanian National Defence Volunteer Forces | 1991– |
 |  India | Indian Home Guard | 1962– |
 Sri Lanka | Sri Lankan Home Guard | 1986– | |
 |  Poland | Polish Territorial Defense Force | 2017– |
 |  United States | State defense forces of State governments and Territory governments | 1917– |
 |  Ukraine | Territorial Defense Forces | 2022– |
A militia is generally an army or some other fighting organization of non-professional and/or part-time soldiers; citizens of a country, or subjects of a state, who may perform military service during a time of need, as opposed to a professional force of regular, full-time military personnel; or, historically, to members of a warrior-nobility class. When acting independently militias are generally unable to hold ground against regular forces; militias commonly support regular troops by skirmishing, holding fortifications, or conducting irregular warfare, instead of undertaking offensive campaigns by themselves. Local civilian laws often limit militias to serve only in their home region, and to serve only for a limited time; this further reduces their use in long military campaigns. Militias may also, however, serve as a pool of available manpower for regular forces to draw from, particularly in emergencies.
A paramilitary is an organization whose structure, tactics, training, subculture, and (often) function are similar to those of a professional military, but which is not part of a country's official or legitimate armed forces. Paramilitary units carry out duties that a country's military or police forces are unable or unwilling to handle. Other organizations may be considered paramilitaries by structure alone, despite being unarmed or lacking a combat role.
National guard is the name used by a wide variety of current and historical uniformed organizations in different countries. The original National Guard was formed during the French Revolution around a cadre of defectors from the French Guards.
The Home Guard was an armed citizen militia supporting the British Army during the Second World War. Operational from 1940 to 1944, the Home Guard had 1.5 million local volunteers otherwise ineligible for military service, such as those who were too young or too old to join the regular armed services and those in reserved occupations. Excluding those already in the armed services, the civilian police or civil defence, approximately one in five men were volunteers. Their role was to act as a secondary defence force in case of invasion by the forces of Nazi Germany.
The Auxiliary Units, Home Guard Shock Squads or GHQ Auxiliary Units were specially trained, highly secret quasi military units created by the British government during the Second World War with the aim of using irregular warfare in response to a possible invasion of the United Kingdom by Nazi Germany, "Operation Sea Lion". With the advantage of having witnessed the rapid fall of several Continental European nations, the United Kingdom was the only country during the war that was able to create a multilayered guerrilla force in anticipation of an invasion.
Irregular military is any non-standard military component that is distinct from a country's national armed forces. Being defined by exclusion, there is significant variance in what comes under the term. It can refer to the type of military organization, or to the type of tactics used. An irregular military organization is one which is not part of the regular army organization. Without standard military unit organization, various more general names are often used; such organizations may be called a troop, group, unit, column, band, or force. Irregulars are soldiers or warriors that are members of these organizations, or are members of special military units that employ irregular military tactics. This also applies to irregular infantry and irregular cavalry units.
Auxiliaries are support personnel that assist the military or police but are organised differently from regular forces. Auxiliary may be military volunteers undertaking support functions or performing certain duties such as garrison troops, usually on a part-time basis. Unlike a military reserve force, an auxiliary force does not necessarily have the same degree of training or ranking structure as regular soldiers, and it may or may not be integrated into a fighting force. Some auxiliaries, however, are militias composed of former active duty military personnel and actually have better training and combat experience than their regular counterparts.
SS Heimwehr "Danzig" was an SS unit established in the Free City of Danzig before the Second World War. It fought with the German Army against the Polish Army during the invasion of Poland, and some of its members committed a massacre of Polish civilians. After this it became part of the 3rd SS Totenkopf Division and ceased to exist as an independent unit.
In the American Civil War the Home Guard or Home Guards were local militia raised from Union loyalists.
In various theaters of operations in the Portuguese Colonial War arose at the outset the need to create various types of irregular forces to help the Portuguese Armed Forces.
A field force in British and Indian Army military parlance is a combined arms land force operating under actual or assumed combat circumstances, usually for the length of a specific military campaign. It is used by other nations, but can have a different meaning.
The Anti-Communist Volunteer Militia were paramilitary auxiliary formations of the Royal Italian Army composed of Yugoslav anti-Partisan groups in the Italian-annexed and occupied portions of the Kingdom of Yugoslavia during the Second World War.
The Arkansas State Guard was the official state defense force of the state of Arkansas during World War II. The Arkansas State Guard was created to fulfill the state missions of the Arkansas National Guard while the National Guard was deployed abroad during World War II. As a military unit trained and funded solely by the state, it was immune to federal activation and deployment, unlike the National Guard. As a part of the official militia of the state of Arkansas, it traces its roots back to the militias which fell under state authority prior to the Militia Act of 1903. The Arkansas State Guard is currently inactive following deactivation after the end of World War II; however, the legal framework for a state defense force still exists, making future reactivation of the Arkansas State Guard by the Arkansas General Assembly legally permissible.
The Ustaše Militia was the military branch of the Ustaše, established by the fascist and genocidal regime of Ante Pavelić in the Independent State of Croatia (NDH), an Axis puppet state established from a large part of occupied Yugoslavia during World War II.
The Vermont State Guard (VSG) is the all-volunteer state defense force of the state of Vermont. The Vermont State Guard serves parallel to the Vermont National Guard, acting as a reserve force for the State of Vermont Military Department. The Vermont State Guard is a reserve force composed of individuals living as civilians when not activated, but the force can be activated in the event of an attack or natural disaster to serve as a force multiplier for the National Guard, and is assigned to fulfill the state mission of the National Guard when the National Guard is deployed.
The Delaware State Guard is the currently inactive state defense force of the state of Delaware, which was active during both World War I and World War II. As the official militia of the state, the Delaware State Guard was created with the intent of acting as a stateside replacement for the Delaware National Guard while the National Guard units were deployed abroad.
The New Hampshire State Guard (NHSG) is the currently unorganized state defense force of New Hampshire. The purpose of the State Guard is to augment or replace the New Hampshire National Guard by assuming the National Guard’s stateside duties when any part of the National Guard is federalized. However, unlike the National Guard, the State Guard is a purely state-level military force which cannot be federalized or deployed outside the state of New Hampshire. The NHSG is a component of the organized militia of New Hampshire.
The South Dakota State Guard is the currently inactive state defense force of South Dakota. The State Guard is recognized as a military force separate from the South Dakota National Guard. Unlike the National Guard, the State Guard is a purely state-level military force under the command of the Governor of South Dakota, and cannot be federalized or deployed outside the borders of the state. The South Dakota State Guard was active during World War I, World War II, and the Vietnam War and provided military protection to the state of South Dakota while the National Guard was in federal service.
The Illinois Reserve Militia was the state defense force of Illinois during World War I and World War II. After the Illinois National Guard was federalized, the Illinois Reserve Militia was organized to assume the stateside duties of the National Guard.
