During World War II, the reservation was used as a prisoner-of-war camp for Filipino and American soldiers captured by Japan during its successful invasion of the Philippines.

It housed the Training Command's Philippine Army Officer Candidate School, NCO Academy, and Headquarters Service Battalion.

[3] In August 1941, Camp O'Donnell was built on a 250-hectare plot of land about 65 miles north of Manila, the capital city of the Philippines.

When the camp's inmates were ordered to repel the approaching Japanese forces, building on the facility was put on hold.

The prisoners were forced to undertake the Bataan Death March of approximately 145 kilometres (90 mi) to arrive at Camp O'Donnell.

The Japanese military leadership was ill-prepared to handle the incarceration of almost 70,000 Prisoners of War, and did not have the logistics or facilities prepared at the camp to support such influx of population.

The Japanese soldier was the product of a brutal military system in which physical punishment was common and so they treated the POWs accordingly.

Moreover, the Filipino and American soldiers arriving at Camp O'Donnell were in poor physical condition and had survived on short rations for several months.

About 120 senior officers, including General Wainwright, commander of U.S. forces in the Philippines, were taken to a camp near Tarlac City after their surrender at Corregidor in May 1942.

[13] On June 19, 1942, the Filipino swimmer Teófilo Yldefonso, who won the country's first ever Olympic medal, died at the camp aged 38.

Elpidio Quirino included him in the list of pardoned Japanese war criminals, but was to continue his sentence in Sugamo Prison in Tokyo.

The former internment camp is the location for the Capas National Shrine[19] which was built and is maintained by the Philippine government as a memorial to the Filipino and American soldiers who died there.

A huge obelisk now stands as a grave marker on the original site of the camp, which charges an entrance fee of less than Ph₱20 per head.

In 2016, the Bases Conversion and Development Authority commenced construction work of New Clark City at the former American camp.