A concentration camp is a government-run site where civilians are detained because of who they are — their ethnicity, religion, nationality, politics, or membership in some other group the state has decided is threatening — rather than because of anything they have been individually charged with or convicted of. The United States Holocaust Memorial Museum describes it generically as “a site for the detention of civilians whom a regime perceives to be a security risk of some sort,” and stresses that “incarceration in a concentration camp is independent of any judicial sentence or even indictment, and is not subject to judicial review.”1United States Holocaust Memorial Museum. The Nazi Camp System: Terminology The word itself comes from the practice of physically concentrating a targeted civilian population into a confined, guarded space. That definition of a concentration camp is the working definition used by historians, human rights organizations, and international lawyers, and it applies to a much wider range of situations than the Nazi camps that made the phrase infamous.
What Separates a Concentration Camp From a Prison
The defining feature is the basis for confinement. Prisons hold people convicted of specific offenses through a legal process. Concentration camps hold people because of a shared characteristic the state has decided is dangerous. No individual accusation is required. Entire communities are swept up together.
This group-based logic drives everything else. Authorities do not need to prove that any particular person did anything wrong. They classify a demographic as threatening and physically relocate its members into a controlled area. Children, elderly people, and those with no connection to any conflict are detained alongside everyone else. The decision is administrative, not judicial. No judge signs an order. No lawyer argues a defense.
Scale follows from that logic. Because the target is a group rather than individuals, the numbers run into the thousands or hundreds of thousands, and facilities are built or repurposed quickly for volume rather than humane conditions. That is where the word “concentration” does its work: a dispersed population is gathered and compressed into a single controlled location, making it easier to monitor, isolate, and exploit.
How This Differs From an Extermination Camp
The terms concentration camp and extermination camp are often used interchangeably, but they describe different things. Concentration camps are sites of indefinite detention, forced labor, and brutal conditions where large numbers of people die from starvation, disease, exhaustion, and violence. The Nazi concentration camps served three broad functions: indefinite incarceration of perceived threats, elimination of targeted individuals, and exploitation of prisoner labor.1United States Holocaust Memorial Museum. The Nazi Camp System: Terminology Death was pervasive, but the camps were not built solely to kill.
Killing centers were. Facilities like Belzec, Sobibor, Treblinka, and Chelmno were designed from the outset for the industrial-scale murder of people upon arrival. Most victims were killed within hours of stepping off the transport trains. A small number were kept alive temporarily to sort belongings or dispose of bodies, but the entire architecture served one function.1United States Holocaust Memorial Museum. The Nazi Camp System: Terminology Auschwitz-Birkenau occupied a grim middle ground, functioning as both a concentration camp and a killing center.
The distinction matters for the definition. Every extermination camp is an atrocity, but not every concentration camp is an extermination camp. A facility can meet the definition of a concentration camp without being built for mass murder, which is why the term applies to a much broader range of historical situations than the Holocaust alone.
Where the Term Comes From
The modern concept emerged in the late nineteenth century in colonial wars. In February 1896, Spanish General Valeriano Weyler implemented a reconcentración policy in Cuba, ordering rural civilians into fortified towns within eight days and shooting those who refused. By 1898, roughly one-third of Cuba’s population had been forced into the camps, and more than 400,000 Cubans died as a result.2PBS. Crucible of Empire The policy is widely cited as the origin point of the modern concentration camp.
The British used a similar strategy during the Second Boer War in South Africa (1899–1902), confining Boer families and Black Africans in a network of camps to cut off support to guerrilla fighters. Around 28,000 Boers, mostly women and children, and roughly 14,000 Black Africans died in the camps.3National Army Museum. Boer War
The most extensive use came under Nazi Germany. Between 1933 and 1945, the Nazi regime and its allies established more than 44,000 camps and incarceration sites of various kinds. Deaths in the concentration camp system alone, excluding the killing centers, are estimated between roughly 800,000 and 955,000 registered prisoners; including Auschwitz and Majdanek, the figure rises above two million.4United States Holocaust Memorial Museum. Concentration Camp System: In Depth
The definition also fits closer to home. In 1942, Executive Order 9066 authorized the removal of roughly 122,000 Japanese Americans from the West Coast into fenced, guarded camps. No individual charges were filed; entire families, including U.S.-born children, were detained based on ancestry. In 1988, the U.S. government formally apologized and provided a $20,000 payment to each surviving detainee.5National Archives. Executive Order 9066: Resulting in Japanese-American Incarceration The U.S. State Department has documented China’s mass detention of more than one million Uyghurs and other Muslim minorities in as many as 1,200 state-run internment camps across the Xinjiang region, described by Chinese authorities as “vocational training centers.”6U.S. Department of State. Forced Labor in China’s Xinjiang Region
What International Law Says
International law does not ban internment outright, but it sets strict conditions. Article 42 of the Fourth Geneva Convention allows the internment or assigned residence of protected persons “only if the security of the Detaining Power makes it absolutely necessary.”7International Committee of the Red Cross. Convention (IV) Relative to the Protection of Civilian Persons in Time of War In occupied territory, Article 78 requires a regular procedure with the right of appeal and periodic review at least every six months. Article 79 reinforces those limits by barring internment except in the narrow circumstances the Convention specifies.
When internment does occur, detainees must be treated humanely. Article 76 requires food and hygiene conditions sufficient to maintain health, necessary medical care, and access to visits from delegates of the International Committee of the Red Cross. Women must be held in separate quarters under the supervision of women, and minors must receive treatment appropriate to their age.8International Committee of the Red Cross. Convention (IV) Relative to the Protection of Civilian Persons in Time of War – Article 76 Historically, the gap between these standards and actual conditions inside concentration camps has been enormous.
The Rome Statute of the International Criminal Court adds personal criminal liability. Article 7 includes within crimes against humanity “imprisonment or other severe deprivation of physical liberty in violation of fundamental rules of international law” when committed as part of a widespread or systematic attack against a civilian population. Article 77 authorizes imprisonment of up to 30 years, or life imprisonment when the gravity of the crime warrants it, along with fines and forfeiture of proceeds and assets connected to the crime.9International Criminal Court. Rome Statute of the International Criminal Court Enforcement depends on cooperation from member states, and political realities often frustrate accountability.
The Legal Mechanism That Makes Them Possible
Every historical concentration camp shares a common legal move: the suspension or circumvention of normal judicial protections. Governments do not build mass detention facilities inside the ordinary legal system, because that system would reject them. Individual charges, evidence hearings, defense counsel, and appeals all stand in the way of rounding up entire communities.
So governments go around those protections, typically by invoking emergency powers. In the United States, the Constitution provides that the writ of habeas corpus, the right to challenge the legality of your detention before a judge, “shall not be suspended, unless when in Cases of Rebellion or Invasion the public Safety may require it.”10Constitution Annotated. Suspension Clause and Writ of Habeas Corpus Elsewhere the pattern is similar. States declare an emergency, classify a population as a threat, and authorize administrative detention that bypasses the courts. By labeling the confinement administrative rather than punitive, authorities try to sidestep the protections that would apply to anyone facing criminal charges.
The result is a parallel system in which the executive decides who is detained, for how long, and under what conditions, with little outside oversight. That combination of group-based targeting, administrative authority, and the absence of judicial review is what turns a detention site into a concentration camp under the definition historians and international bodies use.