Technically speaking those aren’t datacenters, they’re regions. AWS regions can have multiple AZs, and each AZ can have multiple datacenters spread around a city, each with different latency characteristics. This is completely opaque to customers, you don’t really get to choose which one you’re in. There are ways to gain info about it though.

This is way outdated now but gives a rough idea: https://wikileaks.org/amazon-atlas/document/AmazonAtlas_v1/A...

Source: did some latency work for a market maker.