auto fill state and city from phone number?

Hi,
I have a long column of phone numbers, and would like to program the adjacent columns to autofill the State and City for the phone numbers. The only way I can think to do this is to create a massive formula, but including every single zip code and corresponding state, city seems like a nightmare. Is there an easier way to to this? If there's not, what's the best way to word the formula?

Thanks,

Biz

Without posting your specific situation, you might only get general responses, like 'use a lookup table'.

Do you have:
•A separate listing of all phone numbers and corresponding addresses?
•Listings of Area Codes/Regions, Prefixes/Cities, etc?
(Note: that with portable phone numbers, prefixes may not accurately refer to Cities?
•Any other information to help with a solution?

Regards,
Ron

Hi Ron-
Yes, I have a separate listing of area codes and their corresponding city & state. How could I set up document A's columns to consult the second document to autofil the City and State fields?

Thanks,

Biz