Which pattern? The pattern that shows a clear propensity to end with an “a” any state or country name that begins with an “a”. It happens at a rate double or more than any other starting letter. There are more than enough “a” to “a” examples (20) to reasonably demonstrate the pattern. It’s not like I asked why every country that starts with a “q” ends with an “r”.
And, yes, “a” to “a” is an outlier, which is kind of my point.
And all those countries that end in -istan or -stan: that’s an ending meaning roughly ‘land of the’. So Afghanistan is ‘land of the Afghans’, Pakistan is ;land of the Paki’s (pure)’, etc.
The smallness of your sample size, coupled with the tendency for country names to end in “a”, is distorting your perception.
If you look at a bigger sample including other types of toponym, for example names of counties, you’ll see that the vast majority of ones that begin with “a” do NOT end in “a”.
Small sample size + random fluctuations + tendency of country names to end in “a” + confirmation bias = spurious conclusion.
Yeah, they all end in “y” (or “h” in Louisiana). 
Counties are kind of a bad example because the vast majority of counties are just someone’s name, as opposed to a word specifically devised to be a place name. Just skimming that list, it looks to me like “a” endings are indeed over-represented among the county names that aren’t named after a specific person.
Okay, okay, okay, we’ll say it! It’s all part of the Illuminati’s Secret Master Plan! And now that it’s out in the open, they’re going to have to kill all of the penguins to get things back on track! That’s right, little dead penguins! Are you happy now?
You mean the penguins that live in…ANTARCTICA??!!
Oh, come on! You probably thought of 2 or 3 examples and thought that covered the entire world. Well, it obviously doesn’t.
Here’s a list of those that do end in N:
Yemen
Yerevan, Armenia
Yangon, Burma
Yunnan, China
Yucatan, Mexico
Yukon, Canada
Yilan, Taiwan
Yunlin, Taiwan
Yasothon, Thailand
And here’s a list where they don’t:
Yardimli, Azerbaijan
Yevlax, Azerbaijan
Yambol, Bulgaria
Yomou, Guinea
Yoro, Honduras
Yazd, Iran
Yamagata, Japan
Yamaguchi, Japan
Yamanashi, Japan
Yanggang, N Korea
Ysyk-Kol, Kyrgyzstan
Yap, Micronesia
Yobe, Nigeria
Yaroslavl’, Russia
Yala, Thailand
Yalova, Turkey
Yozgat, Turkey
Yumbe, Uganda
Yaracuy, Venezuela
Yen Bai, Vietnam
Note that both lists contain things usually labeled prefectures, districts, regions, oblasts, and a few other synonyms of state/province. I didn’t discriminate on that basis – any 1st level administative division was included. Names were taken from this page of the CIA World Factbook.
Thank you for that link. Up until now we were apparently just using the American states; I added Canada (but I missed Vermont). Since that was what the OP was using, I continued in that vein. I never intended to cover the whole world.
If we use provinces and districts of other countries the idea that states that begin with A always end with A is clearly just a fluke of probability:
Algeria: Adrar, Ain Defla, Ain Temouchent, Alger, Annaba
Brazil: Acre, Alagoas, Amapa, Amazonas
China: Anhui
Columbia: Amazonas, Antioquia, Arauca, Atlantico
El Salvador: Ahuachapan
Those are few quick examples from the first few countries.
Not after next Tuesday.
There is an ethymological reason why many place names end in -a, but it’s got nothing to do with how they start. As mentioned in one of the first posts, the -ia suffix comes from one meaning “land of the…”, so you get lots of People-ias which end in, tadaaaaa… A! — but only for places which got originally named in Latin or in a Romance language, many of which do not have an -a in English but do have one in some Romance languages (not necessarily in all of them).
It most certainly can.
It may or may not be, but it can be.
E.T.A. whats up with H?!!
I’ll assume you realize I wasn’t speaking literally.
0% of countries/states that start with h end with a.
Your reluctance to accept that this may have happened by chance suggests that you were speaking literally.
I understand. I was drawing attention to your lack of surprise at this fact.
Ah. Another incident of light sarcasm not always translating through the keyboard.
Hungaria?
Only if you restrict yourself to US states:
Columbia: Huila
Estonia: Harjumaa, Hiiumaa
Look at the bigger picture; in any small data set there are bound to be statistical anomalies.
Hibernia? Hispaniola? Hollandia?