They're definitely American, and from their appearance, extremely white. Case closed.

Yeah they're american and white, I gotta agree! But, if you see Blisstina (Bliss) from the new Powerpuff Girls, then she's african american and her voice is british!

I think Bliss is British-African.

@Blossomisrobin good idea

The OG PPGs are probably from Western US, since they don't have discernible accents. The new PPGs have annoying New Yorker accents that make my ears bleed!