Most borders between countries (and many internal borders as well) follow natural landmarks, such as bodies of water or heights of land.
However - North America, Australia, and the leftovers from the post-WW1 Ottoman breakup in Asia (e.g. Israel-Egypt or Oman-Yemen) seem to be the only areas of the world where straight-line borders are to be found. (US state counties are almost always straight-lined)
Are there others? Was it just easier to draw straight lines (particularly in flat, waterless areas like US/Canadian prairies or Arabian deserts)?
Bad surveying 200 or so years ago have led to parts of the straight-lined Canada-US border segments to be off by as much as a couple of hundred yards/meters.
Lots of long straight line borders in N. Africa. And some in S. Africa as well. Angola and Namibia, for example, have several straight border sections including parts of that weird Caprivi Strip jutting out of Namibia.
Using rivers as borders can be troublesome over time as rivers, esp. ones in flat floodplains, tend to change their course pretty frequently. Examine the borders of Arkansas, Louisiana, Tennessee, and Mississippi (the state) to see how much the course of the Mississippi (the river) has changed since the borders were drawn-note the huge number of oxbow lakes where the border is, with the main channel now several miles away.
In general principalities expanded until they reached some sort of natural boundary with a neighboring principality. If no such natural boundary existed, an artificial (straight) line would be drawn.
Of course with the rise of colonialism borders were set by people far, far away. Cue Sir Reginald Mapsalot III:
Europe’s irregular borders are usually either a case of the border following some natural feature such as a river or a mountain range, or a result of centuries of fighting over or otherwise trading territory. This can lead to very complicated demarcations, such as the situation in Baarle-Hertog between Belgium and the Netherlands.
The straight line borders (well, technically, they’re arcs, of course) in America and Africa are the result of boundaries that developed much faster than they did in Europe. Either two colonial powers would come to an agreement to delineate territory between them, or the country itself would, after independence, set up a number of subnational entities and draw straight lines for convenience.
You’ll find these even in Antarctica, which is subject to territorial claims made by some countries (though not recognised by every other country), and these claims are usually also delineated by straight lines.
Here is a cool video about what has happened when a border got moved from a river to a main street in the town. It was moved before the concept of international boundaries were a thing but now it is the border between Germany and the Netherlands.
This is correct. In northern VT on I-91 or maybe I-89, there is a sign maybe a half mile south of the border that says 45 deg N, halfway between the equator and the pole. Actually that’s correct in degrees not miles. On account of the oblateness of the earth, the distance from 45 to the pole is less than that between 45 and the equator.
Incidentally the border between US and Canada is not completely determined. At some places between Alaska and the Yukon, it is defined by height of land. But the land is under a couple miles of ice and has never been surveyed (not that anyone cares).
Fun fact - look closely at the border between Manitoba and Saskatchewan, and it’s actually stepped. AIUI, that’s so that the Manitoba sections (square miles of farmland allocation) could stay square despite the curvature of the earth.
A lot of straight lines were either:
-laid out before major settlement arrived, so a tidy solution before things got messy. A lot of US states are like this.
-laid out by/between colonial powers with little regard for the ehtnic groupings they were splitting up by drawing those lines (Not applicable in the USA where the indigenous groups were treated as irrelevant)
-laid across unusable terrain - Middle East deserts, deep jungles (see point above) mountain ranges, the frozen north of Alaska/Yukon, etc.
Fun facts -
Point Roberts, a sliver of US territory isolated and reachable only by driving through Canada.
Northwest Angle, a surveying error which results in the again isolated northern-most part of the continental USA just before the 49th parallell starts.
There’s a jog at the easternmost part of the straight line between Egypt and Sudan where they disagree with the straight line - so the southern part of the jog nobody claims, and the northern part Sudan claims as theirs but Egypt had dibs on it.
IIRC there used to be an unclaimed area between Iraq and Saudi Arabia - or was it Kuwait? _ but i don’t see it on the map any more, so I assume Iraq was not able to press its claim over the last few decades.
I’m not quite sure I understand. Zero longitude is defined arbitrarily, but surely zero latitude isn’t? It’s the equator, which is defined by reference to the poles, which, in turn, come from the Earth’s axis of rotation. So latitude, unlike longitude, comes naturally.
The Treaty of Guadalupe Hidalgo defined the border between the US and Mexico as the deepest channel of the Rio Grande, but the river shifted significantly around El Paso due to flooding in the 1860s leaving an enclave of Mexican territory (the Chamizal) north of the river. The final status of the territory wasn’t settled until 1964.
That’s correct. In fact, when the original Manitoba boundaries (the postage stamp) were set out in the Manitoba Act, 1870, they didn’t properly account for the curvature of the Earth and the western and eastern boundaries theoretically met at the North Pole (geographic, not magnetic).
Parliament and the Manitoba Legislature had to correct the boundaries a few years later. The Preamble to the correcting Act explained the problem:
And whereas the boundaries of the Province, as above described, upon the east and west converge as they extend northward from the forty-ninth parallel and do not correspond with the system of rectangular survey which has been adopted in the said Province and the North-West Territories ;
All of the ways of defining latitude agree on 0º and 90º, but they disagree in between. You could measure distance from the equator to the pole along the surface, and call 1/90 of that distance one degree. You could take a line from the center of the Earth to your point, and another line from the center of the Earth to the equator, and measure the angle between those two lines. You could take a line perpendicular to the surface, and measure that angle. And I’m sure there are a lot of other possibilities I’m not considering.
All of these methods give the same result for a sphere, but they all give different results for an oblate sphereoid.
It’s not post-WW1; instead, it was drawn in the second half of the 19th Century between the Ottoman Empire and Egypt, which was a British protectorate at the time. The British after 1917 and Israel after 1948 kept the border as is.
It’s not completely straight. If you look closer, you’ll see a few slight angles, as well as a squiggle about halfway through. Israeli schoolkids are told that the squiggle is because the cartographer had his hand on the map and drew around his fingers; in fact, I think the Turks wanted to keep control of a couple of strategic wells.
