Route 3 continues to carry the Seaway Trail north along the eastern shore of Lake Ontario. East of Sackets Harbor, Route 3 turns east toward the city of Watertown. The Seaway Trail instead turns north again along NY 180. Just north of the village of Dexter, the trail turns northwest along NY 12E. Route 12E passes through the village of Chaumont and turns west around Chaumont Bay, then turns northwest again to Cape Vincent. Here, Route 12E turns sharply to the northeast, just an eighth of a mile (200 m) from the shore at the headwaters of the St. Lawrence River. Canada, specifically Wolfe Island, is just across a narrow channel. Route 12E continues northeast along the river. Route 12E ends at its parent route, NY 12, in the village of Clayton. Route 12 continues to carry the Seaway Trail northeast to the county line, passing through Alexandria Bay.