A region is a geographic area where resources used by your ECSs are located.
ECSs in the same region can communicate with each other over an intranet, but ECSs in different regions cannot.
Public cloud data centers are deployed worldwide. Creating ECSs in different regions can better suit certain user requirements. For example, applications can be designed to meet user requirements in specific regions or comply with local laws or regulations. ECS pricing also changes based on region.
Each region contains many AZs where power and networks are physically isolated. AZs in the same region can communicate with each other over an intranet. Each AZ provides cost-effective and low-latency network connections that are unaffected by faults that may occur in other AZs.