West Curtain Wall and Dry Moat
The walled portion of today's Fort York traces the army's 1813-16 replacement post for York constructed shortly after the Battle of York in April 1813.
An earlier fort, built between 1800-13 and situated about 100 metres east of today's garrison, was destroyed by American forces during the Battle of York in April 1813 and in a second raid later that summer. While there is virtually no evidence of the earlier post, some fortification features associated with it survive because they were incorporated into the later fort. These include the west curtain wall, a dry moat (ditch) and the Government House (or Circular) Battery.
Originally, the west wall was a detached earthwork. It was ordered built in 1811 by the Commander of the British Forces in Upper Canada, General Isaac Brock as part of the hardening of British military posts around the Great Lakes just before the War of 1812.
Aligned roughly north-south, the wall was laid out at right angle to the shoreline of Toronto Bay. It protected Government House (Lieutenant-Governor's Vice-Regal residence) from a land assault from the west and provided distant protection for the earlier garrison and Town of York located two kilometres east. Today, the west wall is open at its midpoint with a gated entrance. The original fortified wall was continuous with no gap.
Plaque via Alan L. Brown's site Toronto Plaques. Full page here.