Map - Trnopolje camp (Trnopolje)

The Trnopolje camp was an internment camp established by Bosnian Serb military and police authorities in the village of Trnopolje near Prijedor in northern Bosnia and Herzegovina, during the first months of the Bosnian War. Also variously termed a concentration camp, detainment camp, detention camp, prison, and ghetto, Trnopolje held between 4,000 and 7,000 Bosniak and Bosnian Croat inmates at any one time and served as a staging area for mass deportations, mainly of women, children, and elderly men. Between May and November 1992, an estimated 30,000 inmates passed through. Mistreatment was widespread and there were numerous instances of torture, rape, and killing; ninety inmates died.

In August 1992, the existence of the Prijedor camps was discovered by the Western media, leading to their closure. Trnopolje was transferred into the hands of the International Red Cross (IRC) in mid-August, and closed in November 1992. After the war, the International Criminal Tribunal for the former Yugoslavia (ICTY) convicted several Bosnian Serb officials of war crimes and crimes against humanity for their roles in the camp, but ruled that the abuses perpetrated in Prijedor did not constitute genocide. Crimes in Trnopolje were also listed in the ICTY's indictment of former Serbian President Slobodan Milošević, who died mid-trial in March 2006.

The administrative district (opština or općina) of Prijedor is made up of 71 smaller towns and villages. According to the 1991 Yugoslav census, Prijedor had a total population of 112,470, of which 44 percent identified as Bosnian Muslims (Bosniaks), 42.5 percent as Serbs, 5.6 percent as Croats, 5.7 percent as Yugoslavs and 2.2 percent as "others" (Ukrainians, Russians, and Italians). Prijedor was of strategic significance to the Bosnian Serbs as it connected north-western Bosnia with the Republic of Serbian Krajina (RSK) in Croatia, a breakaway state that had been established by Croatian Serbs in 1991. It was also in 1991 that the Serbs of Prijedor organized and enforced a Serb-only administration in the town and placed it under the control of the Bosnian Serb capital Banja Luka. Milomir Stakić, a physician who had been the deputy to the elected Bosniak mayor Muhamed Čehajić, was declared the Serb mayor of Prijedor.

On 30 April 1992, Bosnian Serb forces seized control of Prijedor. Four-hundred Bosnian Serb police participated in the takeover, whose objective was to usurp the functions of the municipality's president and vice-president, the director of the post office, and the chief of police. Serb employees of the public security station and reserve police gathered in the suburb of Čirkin Polje, where they were broadly divided into five groups of about 20 members each, and ordered to gain control of five buildings, one assigned to each group: the assembly building, police headquarters, courts, bank, and post office. Serbian Democratic Party (SDS) politicians prepared a declaration of the takeover, which was broadcast repeatedly on Radio Prijedor the following day. The International Criminal Tribunal for the Former Yugoslavia (ICTY) would conclude that the takeover was an illegal coup d'état, planned and coordinated long in advance with the aim of creating an ethnically pure municipality. The conspirators made no secret of the takeover plan, and it was implemented by the coordinated actions of Serb politicians, police, and army. Milomir Stakić, a leading figure in the coup, was to play a dominant role in the political life of the municipality during the war.

Following the seizure of power, Bosniaks and Bosnian Croats were removed from positions of responsibility. On 30 May 1992, Prijedor police chief Simo Drljača officially opened four camps (Trnopolje, Omarska, Keraterm and Manjača) where non-Serbs who failed to leave Prijedor were then confined. To avert resistance, Bosnian Serb forces interrogated all non-Serbs that were deemed a threat and arrested every Bosniak and Croat who had authority or power. Non-Serb men of fighting age were particularly targeted for interrogation and separated from women, children and the elderly.