Throughout the course of the Second World War, many troops had passed through Caledon. While officers had headquarters at Caledon Castle or Alexander House, ordinary soldiers camped in Nissen huts.
Belgian soldiers of 5th (Merckem) Infantry Brigade had a base at Caledon Camp, Caledon, Co. Tyrone as they underwent training in Northern Ireland. At the camp, they built a French horn motif of white stones on the ground.