Normal Irn Bru is just made from sugar and rust (OK, ammonium ferric citrate if you're being picky) so it doesn't taste like ginger.
I do recall there being a "spicy" variant a few years ago that did taste a bit like ginger but, as I can't stand Irn Bru at the best of times, I don't recall the details.
Source: married to a Scot that basically lives off the stuff. Bit surprised she isn't magnetic.
For a very long time, I thought "ginger" was something used in England for the most part instead of the US. I don't know where they say it regularly in the US, though. I'm now curious too.
I don't know if it is what the other poster is talking about but Michigan is weird in that a relatively large number of people drink ginger ale as a soft drink, particularly Vernors.
Just for the record to prevent any potential confusion: we Michiganders don't call pop "ginger". We do like our ginger ale though (particularly Vernors, but Canada Dry isn't bad).
There is no option for "ginger".... not impressed ;-)