Since I'm soon to be on the technology job market, I decided to get a handle on where the major technology companies were located. After spending some quality time going back and forth bettween the "Career" sections of different companies and Google Maps, I assembled this:

There are a number of disclaimers here:

• This is geared primarily toward locations that emphasize software engineering roles. I tried to filter accordingly if there are few/no engineering jobs listed for a paricular location, but that may not be perfect either.
• Few companies provided the exact address (Microsoft being one of the exceptions) for every one of their locations, so if Google Maps searches failed, then I just approximated.
• This is certainly not exhaustive; many companies (namely Amazon) have many subsidiaries under different branding, which may or may not have any engineering roles.
• This doesn't include data centers, retail stores, etc.

Let me know if you see any gross errors, or would like me to include any other companies with more than one location. You can get a better view on Google Maps.