best way to get a definitive list of employers in a city (including branch offices)?

Looking to get a list of employers in a city (Portland, OR). I’m particularly keen on employers with branch offices (or headquarters) of larger, multi-state organizations. Not so much so on mom-and-pop one off kinds of places (unless they’re larger).

Are Chambers of Commerce good for this? Or do they focus solely on their membership? Do large entities sign up for token membership in the CoC wherever they do business (thus including them on the list)?

Government sources?

Anything?

This is for all fields of industry - not really looking in one industry or another.

You could start with the Chamber of Commerce, certainly. If the state or area has an Economic Development Authority, they’d likely have these statistics.

It’s also possible that the Census would have collected it, but it might be out of date.

Maybe you want something like the Haines Directory.

Business side of the White Pages?

Contact the Portland mayor’s office. Even if they don’t have specifics, they should have leads for you to pursue.