The museum is split into three sections. The environment, which includes archaeology, vegetation, and animals; the British military presence up to 1922; and, lastly, the Defense Forces.
Over time, the military has become a part of the Curragh, and Curragh have become a part of the Military. The Fianna used to gather at the Hill of Allen; Henry II camped here on his route to Dublin in 1171; and the Jacobite army trained here in 1686-7.