Canada-Places.com has listed approx 36 Historical landmarks in ON. Some of the Top rated Historical landmarks in ON are- Confederation Square, Fort Frederick, Southernmost Point of Inhabited Canada, Trent-Severn Waterway Lock 21 - Peterborough Lift Lock, Rideau Canal Locks 11-12 - Hogs Back, Trent-Severn Waterway Lock 22 - Nassau Mills, Rat Portage Post Marker, Silver Islet Mine, Crawford Lake Iroquoian Village & Killarney East Lighthouse.