Royal Artillery (RA) Park Officers Mess is the oldest military Mess in Canada, serving officers in the Halifax garrison since 1816. The site of RA Park was acquired in1799 from John and Richard Cleary for ₤150, in the name of Prince Edward, to provide soldiers quarters, stores, officers’ accommodations and a headquarters for the Royal Artillery personnel stationed in Halifax. Its acquisition resulted in the move of the royal Artillery personnel and equipment from congested quarters on Argyle Street, opposite Grand Parade, Where the World Trade and Convention Center is now located. Around 1800, the Royal Engineer Establishment consisting of RE Square and the South Barracks were established on the east side of RA Park to provide accommodations for the Royal Engineers. These lands were thus incorporated into the Halifax fortifications, which became collectively known as Imperial Fortress Halifax, with similar status as the Imperial Fortress of Bermuda, Malta and Gibraltar.
          Shortly after obtaining RA Park, several small wooden verandahed barracks were built adjacent to the former main entrance to RA Park on Sackville Street, opposite the road leading up to Citadel Hill. These buildings later became guardrooms. A two and a half story verandahed barracks for 59 soldiers was completed in 1803, running east-west, taking up the north half of the present main parking lot. In 1805, the Commanding Officers Quarters were completed on the east side of the soldiers’ barracks, where it still stands today.