In what part of the world do they use US pennies?

The US currency system sure. But pennies, specifically?

Before Canada stopped using its penny, it was common to find American pennies in circulation.

It's still fairly common to find American nickels, quarters and dimes in circulation. (Probably mostly dimes if I had to guess.) They're generally accepted at par because nobody is even really looking at them and if they did it wouldn't really represent being, well, short-changed.

	▲	whycome 9 hours ago \| parent [-]
		I’ve found that self-checkouts in Canada are a great way to get rid of piles of change. You can pretty much dump it in. Curiously, it will reject all the US coins and spit them back out.