Interestingly I've never heard chimarrão here in Paraná, here it's either chá mate (can be hot or cold) or tereré (cold), so it might be a RS & SC thing.
What? Where you from? I'm from Paraná, and we know Chimarrão... Even other states know Chimarrão, though they don't drink.
Paraguay and also Uruguay, Argentina, Southern Brazil and anywhere where gauchos have moved.
Interesting fact: Uruguay is a heavy consumer of Mate, but doesn't produce any.