To touch on the Portsmouth VA USA (more associated with the larger Norfolk area) thing, I've lived near there. It actually also has a strong connection with the navy too. The largest navy base in the world is in nearby Norfolk, there's a massive shipyard, and a ton of military. The history is obviously not nearly as old though.

The military thing actually removes some of its culture though, because it means a lot of people aren't from there. They're just there for a few years while stationed there and then they're gone. I've never really thought about this, but could this be a deliberate attempt by the US military to destroy a sense of culture for military personnel, to ensure their only loyalty is to the government?