Factual error: During the baseball game in the beginning if you look in the background you can see several palm trees in the background. The movie takes place in Ohio where there are no palm trees. (00:09:15 - 00:10:05)
Suggested correction: Ohio is never specified as the state where the Nightmare movies take place until later in the series. As long as the state is unspecified as it is in Nightmare 2 and 1, visible palm trees are not a mistake.
All the films are supposed to take place in the same city. So if part 6 takes place in Springwood, Ohio, than so does this one.
While it would be true that the location in all previous films are now Ohio, it's hard to say if it's a mistake for the first 5 films, especially if there's no evidence for it being set in Ohio and evidence points to California. It would be more appropriate to make an entry in the 6th film saying the Ohio location contradicts what has been already seen. Otherwise, you would have to make a mistake entry every time the first 5 films reveal it's not set in Ohio, but filmed in California.
Suggested correction: Per the screenplays, the first two movies take place in Los Angeles.
I believe it was Wes Craven's intention to mention it's set in Los Angeles, but the actual script and film never state where Elm Street is located. It was an un-named suburb.