Many members of the Boys were prisoners in the Auschwitz-Birkenau concentration and extermination camp in occupied Poland but relatively few were liberated there. The '45 Aid Society is currently conducting research into establishing how many of the Boys remained in the camp in when it was liberated.
A significant group of five small children who were amongst some of the youngest child Holocaust survivors brought to the UK under the Central British Fund scheme remained in Auschwitz until the arrival of the Soviet Red Army on 27 January 1945.
As the Soviet Red Army advanced into Poland the Germans began to evacuate Auschwitz-Birkenau in November 1944. Prisoners were sent into the Reich proper on death marches, which was the name given to the evacuation by the inmates themselves. Many of the members of the Boys who had been held in Auschwitz were evacuated on these death marches.
Despite the fame of Auschwitz today, the news of its liberation struggled to make it onto the front pages of newspapers in January 1945. The liberation of Majdanek the previous summer had been covered in the Soviet press and a trial had quickly followed, but Auschwitz was largely ignored. The Soviets had no interest in highlighting Jewish suffering, so the Red Army's arrival in Auschwitz was treated as an incidental event in the push westwards. A medical team was left behind to help the survivors who were evacuated out of the camp, many to nearby Katowice. Their experiences there are described by Primo Levi in his novel The Truce.
The five young children who later became part of the Boys were taken to Slovakia and made at least some of that journey on foot crossing the border across the wild Tatra Mountains. They were probably in the care of the adult female prisoner who had been in charge of their barracks. This was the case in a similar barracks for boys, where Dr Mengele kept other children to be used for medical experiments. That group were taken by the barrack leader to Budapest after liberation, probably along the same route.
The five children were taken to the orphanage on Zvornarska Street in Kosice. Other children held by Dr Mengele also made this jounrey. The small future members of the Boys told aid workers that they wished to go to Palestine. The five children were, however, then put in a group of children who were to be taken to the UK and moved to the Belgicka orphanage in Prague.