seventyseven's "Notable parallels"

There are the five major circles of latitude:
- Arctic Circle
- Tropic of Cancer
- Equator
- Tropic of Capricorn
- Antarctic Circle

Also included are other notable parallels that have served to divide territory or have other significance.
- 60th parallel north: divides the western Canadian provinces and the Canadian territories
- 54-40 N: the U.S. claim over southern British Columbia, part of the Oregon Boundary dispute that ended with Western Canada and the Western U.S. having a border at the 49th parallel. (Gave rise to the American slogan "Fifty four forty or fight!")
- 49th parallel north: the Canadian-American border in the west.
- 45th parallel north: The halfway point between the equator and the north pole. Also, part of the border between the U.S. and Canada in the east (Quebec-New York/Vermont.)
- 42nd parallel north: the border between New York and Pennsylvania, and also, an old northern border defined by the treaty of Adams-Onis (http://en.wikipedia.org/wiki/Adams-On%C3%ADs_Treaty) between New Spain and the United States. Today divides California and Oregon. Also, the southernmost point of Canada (Point Pelee, Ontario.)
- Mason-Dixon line: originally at the 40th Parallel, was drawn slightly below it to avoid dividing Philadelphia. The traditional cultural boundary between North and South in the United States. http://en.wikipedia.org/wiki/Mason-Dixon_Line
- 38th parallel north: the dividing line between spheres of influence in Korea. (Originally Russian and Japanese, later American and Soviet.)
- 28th parallel north: border between the Mexican states of Baja California and Baja California Sur.
- 22nd parallel north: border between Egypt and Sudan, partly disputed.
- 17th parallel north: border between Republic of Vietnam and Democratic Republic of Vietnam during the Vietnam (or in Vietnam, American) War.
- 26th parallel south: South Australia’s border with the Northern Territory and part of Queensland.
- 45th parallel south: halfway between the Equator and the South Pole.
- 60th parallel south: the northern boundary of Antarctica, as part of the Antarctic Treaty System.