The 45th parallel of north latitude is the east-west line that marks the halfway point between the equator and the North Pole

In North America, it roughly marks the International Boundary between the United States and Canada between the St. Lawrence and Connecticut rivers (the northern borders of the U.S. states of New York and Vermont with the Canadian province of Quebec), where the parallel is sometimes called the "Canada line". The actual boundary of Vermont lies approximately 1 km north of the parallel due to a cartographic error. The boundary here intersects Lake Champlain, which is shared by the two nations, with most of the lake lying in the United States.

In the western United States, the parallel passes through the Great Plains and Rocky Mountains, intersecting the Pacific coast in Oregon. Throughout the United States the parallel is marked in many places on highways by a sign proclaiming that the location is halfway between the North Pole and the equator.

See also:

45th parallel south