I wrote a small utility to check area codes. You can try it here, if it's helpful.
Enter an area code to do a lookup. Or enter a 2 character state, province, or +1 North American country code to lookup area codes. Enter ? for a list of all area codes.
This uses data from NANPA, the NPA database, npa_report.csv.
And also US/Canada data (city names by area code) from here:
The data is loaded into a database.
The latter source is a little older, so there were some newer area codes missing city lists. I went through the missing area codes and added city names for them. Many were overlays, so I was able to use data from one of the older area codes.
The city lists for each area code are not exhaustive, but should give a general idea of where the area code is located. Some of the Canada area codes have really long lists of cities.