The Military Room is on the ground floor of the four-story tower added to the North wing around 1851. It is primarily about military events associated with Burnley residents and the contains the roll of honour of those who died in the two world wars of the 20th century.
This room was opened as a display room in 1931 when it was known as the Antiquities Room and displayed part of the Egyptology collection. In 1977, it became the Prehistory Room displaying archaeological objects from the local area. The room next door, now the Collectors Room, had since 1948 been the room for the East Lancashire Regiment Collection and in 2002 the Military Room was set up using the cases made for the East Lancashire Regiment Collection in 1948.