You can look here for AWS:
https://aws.amazon.com/about-aws/glo...re/regions_az/
Microsoft Azure's:
https://docs.microsoft.com/en-us/azu...es/az-overview
Both have a lot of gov't contracts and those datacenters are supposedly exclusive to them (the "GovCloud/US Gov" regions).
I wouldn't say it's common nor standard to "get one", no matter your size. If anything being a large city is a disadvantage. LA/NYC are terrible places to have datacenters.