1873 aerial image of Fort Ontario showing the fort with its moat and earthworks (removed 1904) around it, support buildings including laundress quarters, a hospital, ordnance sergeants quarters, a gun shed, mortar mill, quartermaster and engineer department stables and barns to the south, a ravine to the east and southeast, and slips for canal boats and schooners on the west side. At the bottom left hand corner is the quarry that the stone for the walls of the Fort came from, a crane, stone cutters shed, carpenter's shop, and storehouse. The two rows of buildings at the top right of the military reservation was a collection of shanties populated by Irish families called Vinegar Hill, or Toad Vale, squatting on land belonging to the estate of abolitionist Gerrit Smith.