I was trying to find a nice range map showing the global distribution of the Argentine ant (Linepithema humile) for my students but it turned out that I couldn't easily find any range map at all*. So I made my own using the world66 website and a little bit of my own tweaking:
The native range is marked in green, introduced range in the classic shade of warning and danger (red).
Here is the text list of countries as well:
United Arab Emirates
United Kingdom (UK)
United States (USA)
That's a pretty impressive distribution, especially given that the list likely isn't complete.
(Source for range data: Global Invasive Species Database)
*Update 4/2008: Alex has provided a link to a much nicer distribution map in the comments. Thanks Alex!