Other cities on the list have ~half the research spending, plus ALSO large tech industries.

Balitimore-Columbia showed up because of Columbia, not Baltimore. NSA and several other agencies are in or near Columbia, plus the contracting firms who support them.

Isn't Johns Hopkins a medical university? Not exactly a Silicon tech hub.

A "medical university"? Strange, I wonder how I did my PhD in experimental condensed matter physics there :-)

It's a general research-focused university, like MIT. The oldest research-based university in the USA in fact.

Though you're right it's very strong in medicine and all things 'bio' including biochemistry, biophysics, bioinformatics, and biotech.

But it also has a strong astrophysics program, eg the Space Telescope Science Institute is based there.

And the JHU Applied Physics Lab is not too far away too.

But I'm not sure why you feel that med-tech and bio-tech don't contribute to a tech hub. Are you considering tech as purely web tech?

Baltimore has a lot of pure industry, too, totally unrelated to government - though if government work is your style, there's no shortage of it here. Granted, you won't find the same median salary you would in Palo Alto or Mountain View, but you don't have to deal with the same headaches, either.

Johns Hopkins has a medical school. But they have other schools too!

APL, too. And anyway, whence comes the idea that a medical school wouldn't have any use for people in our line of work? Bioinformatics is a thing!