"Why is Oklahoma such a weird shape?"
It seems like most folks are specifically referencing the panhandle when they ask this question - that long, seemingly random strip of land jutting out the left side of the state leaves most sensible folks scratching their heads and possibly breathing a confused wisp of "wtf?" or just simply, "why?"
Well, Oklahoma used to be shaped like an upside-down bowler hat. So, it had two "panhandles", one on each side. This looked a lot more balanced. But after the great Battle of Eastern Tiramisu during the short-yet-significant war between the state of Oklahoma and the state of Missouri, Oklahoma lost the eastern panhandle. The entire war only lasted a few weeks (21 April-19 May 1871), but reshaped the shape of the state of Oklahoma forever. To this day, true Okies will shake their fist to the east and mutter, "F%¤#ing Missouri!"
Now you may be squinting your eyes a little as you think, "hey, now, wait a minute there! Oklahoma wasn't even a state until 1907!" Well, you, Dear Reader, are correct. Perhaps the above paragraph is pure invention.
But the real story of why Oklahoma is shaped that way is just as if not even more ridiculous.
Not surprisingly, it gets back to Texas (the head bull of Team Weirdshape). That little strip of land we now call the Oklahoma panhandle was once part of the Republic of Texas. Because of course Texas was it's own thing before becoming a state. Explains a lot. Anyway, Texas was part of the Republic of Mexico for the longest time, but it (Texas) decided to declare independence from Mexico in 1836. Remember the Battle of the Alamo? Yep, that was in 1836. During that year, it applied for annexation to the United States, but was rejected, mainly because it, being a huge -and pro-slavery- state, would be a massive addition to the band of slave-holding states. They also didn't want a war with Mexico (whose government had abolished slavery, by the way). There was a lot of back and fourth over the following years (that is one hot crazy mess for another time), but long story short, Texas became the 28th state in 1846. Mexico was not surprisingly not too pleased about that, and so began the Mexican-American War.
ANYWHO, Missouri does come into the story here, if only in namesake - the Missouri Compromise of 1820. What's this about now? Well, the north wanted to prevent the spread of slavery as the US expanded its territory. The south wanted to spread slavery. So this... uh... compromise... was put into place to placate both sides. Missouri was entered into the Union as a slave state and Maine as a free state, and it was decided that slavery was to be prohibited in the remaining lands of the Louisiana Purchase north of the 36°30′ parallel. Yeah, I know... Pretty danged arbitrary. So with this compromise, the expansion of slave states was barred from northward expansion but free to expand westwardly.
Fast-forward to 1846. Texas is about to be annexed to the Union, BUT... Some of the northernmost territory extended beyond the 36°30′ parallel. And instead of doing the decent thing of, I don't know, getting rid of the ability to own other people or something like that, they instead simply whack that little strip off. Purely so they could enter as a slave state. So our little strip of land, now owned by no one, donned the official name of "Public Land Strip".
Now, since it was owned by no one, squatters soon came in to claim squatters rights or whatever, and began building homes and forming little communities and such. And of course outlaws loved to hang out there (on account of it being lawless and all), and folks fleeing the apparently-not-always-long-enough arm of the law found a haven in the Public Land Strip. Ever heard of No Man's Land? Yeah, this strip of land is the original bearer of that name. What's that Wizard of Oz song? "Horse thieves and Cattle Rustlers and Moonshiners! Oh, My!" Or something like that. Since no real law existed, folks trying to cobble together some semblance of a town relied solely on vigilante and mob justice. Violence, chaos and paranoia thrived.
Decades pass with this area remaining in such a limbo, allowing time for a violent culture of the Wild West to fully mature.
Then, in 1890, we have the Oklahoma Organic Act of 1890. No, it was not about organic farming. An organic act was just the generic term used for an act the government put in place regarding territories in anticipation of incorporation to the Union. Our No Man's Land strip was lumped into Oklahoma Territory, along with some other "leftovers" that were just... hanging around, I guess. Note that much of the now-state was made up of Indian Territory, largely dominated by what remained of the lands belonging to the Five Civilized Tribes (their support of the Confederacy during the Civil War was a used as an excuse for the US government to take even more from Natives). Indian Territory tried to enter the Union as a State of Sequoyah, but that was rejected by Washington. The Five Civilized Tribes act of 1906 tore down a lot more of the tribal rights.
The final shape of the state was settled with the Enabling Act of 1906, where the territories were given the ability to elect delegates to a state constitutional convention and to enter the Union as one whole state (so, combining Oklahoma Territory and Indian Territory). Oklahoma entered the union as the 46th state on 16 November 1907.
Not all that long after statehood, the panhandle became the epicenter of the Dust Bowl of 1935-1938. Some folks tried to stay, others fled towards California. Or tried to, anyway. Ever read Grapes of Wrath? Yeah, that's the Dust Bowl.
Today the panhandle is still sparsely populated, but it's an amazing contribution to the state's biodiversity. Some of the habitat and species there are found nowhere else in the state! So if you get a chance to check out Black Mesa give a "hello" to some of the very special Odonata you can only find in that part of Oklahoma. Just... good luck finding a hotel.