This a perhaps the best parallel to know about, even better than the equator.
I should point out straight away that I have a mnemonic for the details of the 45th parallel that I won’t go into in this article, which presents a more high-level general conceptual perspective. You can read about it if you click the link:
A Mnemonic for the 45th Parallel North made of Nonsense Syllables.
Every country, and every United States state and Canadian province on it.
It lies halfway between the equator and the north pole, and so it is very easy to visualize where it is. This is because 45 degrees is half a right angle, but you knew that.
The 45th parallel north cuts the biggest and most well known nations: Russia, China, the United States, and Canada. The European Union is cut by it, too. And the Mediterranean Sea (and the Black Sea if you don’t think of it as part of the Med) and the North Atlantic, and the North Pacific, and Japan.
This alone makes it far more useful to know than the equator, which cuts only one fairly big and well known nation, Brazil.
Besides cutting all the top nations, and several well-known and important regions like the continent of Europe, the Mediterranean Sea, it cuts them in memorable places, and cuts some smaller, less well known nations in memorable places as well.
It cuts Russia and Canada near each one’s southern tip(s), and China and the contiguous United States at their northern borders, which is memorable.
It is easy to recall where it cuts the continent of Europe: it cuts off the three great southern peninsulas: the Iberian Peninsula, peninsular Italy, and the Balkans.
It just clips the northern tip of the Mediterranean Sea at the northern tip of the Adriatic Sea, at the Gulf of Venice, and cuts off the Mickey Mouse ears of the Black Sea at their bases. This is also memorable.
The Med, the Black Sea and the Caspian sea can be thought of as a triplet, all cut near their northern tips by the 45th parallel.
Japan is cut a smidgen south of the northern tip of Hokkaido, its northernmost (big) island.
Moving on to less well-known countries cut by the 45th parallel, it’s memorable that Crimea is cut (especially if it is considered to be the southern tip of Ukraine), Kazakhstan is cut at it’s southern border, as is Mongolia.
A group of six little-known new nations that I call the “Smaller Stans” (because they are smaller than the huge Kazakhstan), are as a group cut at their northern tip by the 45th parallel (at the northern tip of Uzbekistan). The group is easily recalled by the mnemonic PATKUT:
Pakistan, Afghanistan, Tajikistan, Kyrgyzstan, Uzbekistan, Turkmenistan.
So, by a happy coincidence, the 45th parallel cuts most areas of interest in memorable places, usually either roughly along the northern border, or along the southern border, or at the northern tip or the southern tip. Maybe this coincidence is partly an illusion created by me, and my ability to see patterns where there is none, but in the end it doesn’t matter much. It works (for me, at least).
Just so you know I’m not making any of the facts up, here is a Wikipedia article has a table of data for the 45th parallel and a basic map:
45th parallel north - Wikipedia
The 45th parallel north is a circle of latitude that is 45 degrees north of Earth's equator. It crosses Europe, Asia…
Here’s a clearer map that shows the 45th parallel:
The 45th Parallel Big Four: Russia, Canada, the contiguous US and China in more detail.
Russia is cut extremely memorably by the 45th parallel. In a remarkable (and convenient) coincidence, Russia is cut near its southernmost point, and the panhandle there contains the intersection of the 45th meridian with the 45th parallel. By the way, this panhandle contains the city formerly known as Stalingrad (renamed Volgograd in 1961), where the tide of WW2 turned, at the Battle of Stalingrad (two million casualties).
It gets better. The other place Russia is cut by the 45th parallel is another panhandle, this one, by a stupendous coincidence, containing the intersection of the 135th meridian with the 45th parallel. It’s exactly 90 degrees due east of the one near the southern tip of Russia. Furthermore, the southern tip of eastern half of Russia is in that panhandle, just a smidgen less far south than the southern tip of Russia. How wonderfully memorable. Vladivostok is also in that eastern southern panhandle, extremely near its southern tip, but that’s by the bye. That southern tip near Vladivostok is at the meeting point of Russia, North Korea, and the Sea of Japan (a peripheral sea of the Pacific Ocean, but you knew that).
I can, if I really make an effort, see in my mind’s eye the outline of Russia as that of an eastward charging bull-like monster with a bent tail (the Kola Peninsula — no connection to the kola nut of Coca-Cola fame), a lump on its back (the northern coast of the — intentionally? — phallic Krasnoyarsk Krai) and a large pointed pendant hanging from its neck or chin(the Kamchatka Peninsula), and held aloft, a head (not much of a head although I can imagine a small elephant’s trunk there) which is where Chukotka Autonomous Okrug is — the least densely populated federal “subject” (something like “province” or “state”). The latter contains easternmost point of Russia (which is actually so far east as to be in a sense west, because it on the far side of the 180 degrees line, i.e. in the western hemisphere).
The feet would be these twin southern panhandles separated by exactly a quarter of the 45th parallel. It’s not very clear, but better than nothing (it works for me). Knowing exactly where the ‘feet’ are gives you a rough idea of where the rest of Russia is.
By the way, I think the 45 x 45 points doesn’t get as much attention as it deserves. Likewise the 45 x 135 points. As I explain in the China section of this article, the 45 x 90 points get a lot of attention, including a Wikipedia article about them, maybe because one of them is in the US.
Canada like, Russia, can be thought of as having a pair of foot-like panhandles that are the only parts of the nation south of the 45th parallel, which is very memorable. In Canada’s case, though, the feet are fairly close together at the eastern end of the country. The bigger of the two is the southernmost part of Ontario and contains the southern tip of Ontario and of Canada. Unfortunately, its longitude is nothing special, at about 80 degrees west.
The other foot, on the far side of the United States’ New York State and New England, and the Bay of Fundy, is Nova Scotia. It extends just a smidgen south of the 45th parallel. There is also a tiny bit of New Brunswick south of the parallel on the western side of the Bay of Fundy. This other foot has an uninteresting longitude.
The feet are much smaller and much more crooked than the Russian pair of feet, but their existence shows how similar the latitudes of southern Russia and southern Canada are.
In my mind’s eye I see a large creature with a large mouse-like head (containing Quebec and and the part of Newfoundland and Labrador known as Labrador) and tiny mouselike front paws. The part of Newfoundland and Labrador known as Newfoundland is directly under and almost touching the nose of the head. The creature seems to have no back legs.
The United States.
The contiguous US is in a way the opposite of Canada. It is entirely south of the 45th parallel except for two ‘feet’ that extend north across it — need to imagine an animal lying on its back. The western foot is incredibly wide, like a snail’s foot, and is a bit frayed where the Great Lakes are, while the other foot that is at the extreme east is more panhandlelike. The former contains all or part of a number of states running from Washington to Michigan, while the latter is made up of New York State and the states of northern New England (Vermont, New Hampshire, and and especially Maine).
I see in my mind’s eye a snail on its back with a long foot (or nose) like a crooked elephant’s trunk.
Like the contiguous US, China seems to hang off the 45th parallel like an irregularly shaped piece of paper stuck to a washing line. The northernmost and southernmost points of China not much different from those of the contiguous US and the latter is entirely due east of China. The area of China is almost exactly the same as the total area of the US including Hawaii and Alaska (the noncontiguous parts of the US), and so it bigger than the contiguous US, but not by much. These northward bulges don’t look much like feet, but they do each contain an interesting intersection, with the 90th meridian east , and the 120th meridian east. So these lumps are about 30 degrees apart on the 45th parallel.
The intersection with the 90th meridian is a very special one. It is one of the four “45 x 90 points”. There is even a Wikipedia article about these points, that’s how special they are:
45×90 points - Wikipedia
The 45×90 points are the four points on Earth which are halfway between the geographical poles and the equator, while…
The one in the “left lump/horn of China” is one of only two that are on land. The other is in the US state of Wisconsin. So that is pretty memorable.
In fact, China is about the same size and shape as the contiguous US, and on about the same set of latitudes, and is about 180 degrees due east and west of the US, which makes it very simple to recall where it is, and how big it is and what shape it is.