WaPo reporter spent time in Tampa Bay area researching "Top Secret America"

"You can find it with contracts, job sites, and websites primarily, and then a lot of foot work, where I would go out to addresses that I had, and then look around and find other buildings that they sort of fit the security profile of those that we knew about." She says her and Arkin then put those addresses in their database or put those addresses through some "deep Web searching."

What they learned was that many of these units were clustered around places like MacDill Air Force Base in Tampa, the home of U.S. Central Command and Special Operations Command. And that many who work in those buildings are private contractors, officially not with the government.

"So I’ve been in places in St. Petersburg and the St. Pete/Tampa area. I tooled around there in my car for a number of days doing this sort of work, where I found a whole neighborhoods of these business parks that, if you drive by and you don’t know what you’re looking for, they look like any other business park, but if you do know what you’re looking for, you can see that they are part of this network that we’re describing."

This is what Priest and Arkin dubbed the "alternative geography of the U.S.” And though the Washington D.C. - Baltimore region has by far the most of these "secret" government organizations, Priest says places like Tampa, Los Angeles and Colorado are the next biggest in terms of those affiliated with working for the government in some form on counterterrorism efforts.

Priest says that of the 860,000 people that have acquired since 9/11, about 250,000 of them are private contractors.

We'll have more on our interview with Priest in a subsequent post.