Mine (Zimbabwean 🇿🇼) is the mbira.
For a feel of the sound: https://youtu.be/R5RMYh-n3LU?si=1gMWzw6l6UxxpiLr
Jah Prayzah the guy singing is a renowned musician.
They seem to be using the mbira in modernized covers, but the metal pestle order seem the same as the more traditional looking ones.
P/S I'm not self promoting the YouTube link. It just shows how the mbira sounds unedited.
nyckelharpa 🇸🇪
The Valiha ; it's basically a tube guitar lol
Didgeridoo
If you've listened to Nordic metal at all I'm sure you've heard it in some song
USA alone is too easy, so I'm gonna go with Ohio. Edison invented the phonograph, which made listening to music anytime and anywhere a reality. The Wurlitzer organ was from Cincinnati, but i should be fair and say that while it was developed in Cincinnati, production was done in New York.
The drum kit or set - USA:
It has 120 strings and you play it with sticks and a foot: the cimbalom.
A guy in the 19th century Budapest modernized the ancient hammered dulcimer by adding a dampening pedal and rearranging the strings.
Canada gave us the Ugly Stick and the Sackbut.
The cajon in Peru is emblematic of traditional Creole music that is often played in songs during lunch or party meals. Just hearing it makes me hungry!! 
Btw the mbira has a beautiful sound, do you know if it’s difficult to learn?
Lot's a of kids learn to play a 5-string version, but it goes up to dozens of strings, and some have a pedal to control sustain.
The origins of the instrument are finnish, but it's also popular in Japan, which is why you'll see a lot of stuff online about it in Japanese. Including the video I linked.
The Trautonium.
Saxophone!
The Drumbone was invented in my country.
You asked for one, but I'll try to sneak this in because it actually predates my country by 15 years: the Glass Armonica. Invented in 1761 by Benjamin Franklin himself.
https://en.wikipedia.org/wiki/Glass_harmonica
I think that one is neat. Apparently the US is also responsible for the Electric Guitar, so there's that.
Ugly stick. 🇨🇦
I remember hearing a mbira recording as a young child and loving it. (I didn’t know that word, though, people called it a « thumb piano ».) Then at some point I had the opportunity to try one, but I didn’t know how to play so the result was disappointing, and the metal things made my tiny fingers hurt, ha ha. The video sounds really nice!
I don't know if this counts but in my parent's native Cuba there's the bongo which has African roots. It's a fundamental instrument in Cuba's various local genres such as Son Cubano from which Salsa (not the condiment) derives from. Listening to the mbria I can definitely hear the similarities between native African music and Cuban music.
I'm not Korean, but I've lived here for twenty years. Gayageum is probably the most famous Korean instrument, but I'm partial to the haegeum. https://m.youtube.com/watch?v=OfsFoUell4Y&pp=ygUSaGFlZ2V1bSBpbnN0cnVtZW50
I now wonder if the Mbira is related to the Marimba? They sound very similar, though it seems the Marimba is more central African?
Bacon.
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