exact line. Further east, the 45th parallel roughly marks the Canada–United States border between the St. Lawrence and Connecticut rivers, between the Canadian province of Quebec and the states of New York and Vermont. The parallel is sometimes called the "Canada line" or the Collins–Valentine line. After the Seven Years' War, the 45th parallel was declared the boundary between New York and Quebec. Under the Webster–Ashburton Treaty of 1842, original measurement errors stand so that the boundary is not exactly at 45 degrees north but is where the survey monuments were erected in 1772. The actual boundary of Vermont lies approximately north of the parallel due to an error in the 1772 survey. All of mainland New Brunswick lies north of the 45th parallel. Approximately two-thirds of Deer Island, plus all of Campobello and Grand Manan islands, are south of the 45th parallel. The parallel roughly bisects mainland Nova Scotia. Halifax is approximately south of the parallel. See also 45th parallel south 44th parallel north 46th parallel north 45×90 points Notes References External links The 45th Parallel at the Minnesota Museum of the Mississippi and Other Natural Wonders From the Minas Astronomy Group: Midway from the Equator to the North Pole 45th Parallel Markers Degree Confluence Project n45 Canada–United States border Borders of Montana Borders of Wyoming