Note: USA-specific Not even 20 years ago, before any number could be ported to mobiles, landlines in some (all?) Baby Bell regions had their prefix determined by geography. In other words, you could know what "zone" a given phone number was in by its prefix. Take Silicon Valley. A (650) 960-xxxx number meant Mountain View. (408) 733-xxxx meant Sunnyvale. Etc. Zones roughly respected cities, but boundary conditions ab…
I find the prefixes are a fascinating bit of US telco history. Many of the exchanges had Names for decades. There's a very interesting back and forth between city geography and these exchange names, both in that a lot of actual location names got embedded into them. I've often sometimes wondered too how often that 1950s-era suburbs picked names simply because they fit the exchange name. I feel like that was an underdocumented homogenization force in American suburb names.