Google Earth's directions suggest the M4 at Port Talbot is 'entering England'
Allison Osterwald knew she had to enter England when driving from Swansea to Birmingham but did not expect it on the M4 slip road for nearby Port Talbot.
When looking on Google Earth for directions, the web-based satellite mapping service told her to 'merge onto M4 via the ramp... Entering England'.
College student Ms Osterwald, 40, said: "They are making Wales smaller by the day."
A Google spokesman apologised saying it was "a glitch" which would be fixed.
Ms Osterwald said she turned to Google for help after taking up a friend's invitation to visit her in the West Midlands.
She said: "I was shocked to see that when passing Port Talbot it is classed as, and I quote 'entering England.'"
The mother-of-two and grandmother-of-one said she had lived in Germany for 20 years and so was used to people mistaking Wales for England.
She said: "I explained it as 'England, Ireland, Scotland Wales - we're all Great Britain but we're not all England'.
"I'm from Swansea. I'm positive Port Talbot is not in England. That's wrong. I would have thought something as big as Google would get it right in the first place.
"I will be going on my journey but I might be hitting England a bit later than Google tells me I am."
A spokesman for Google said: "Oops, sorry, our mistake.
"We work very hard to make Google Maps as accurate and helpful as possible for our users - whether searching for business listings, areas of interest or, in this case, finding directions.
"We're constantly working to improve the quality and accuracy of the information in Google Maps and appreciate our users' feedback in helping us do so.
"It will be a glitch from a database. We will look into getting it fixed."