In reference to Nashville and geographic network maps for the United States I found this one
https://personalpages.manchester.ac.uk/staff/m.dodge/cybergeography/atlas/milnet_large.gif
Niprnet, Siprnet security architecture review from 2016 for digging Anons
https://rumble.com/vc73n5-strengthening-practices-niprnetsiprnet-cyber-security-architecture.html