A single AWS environment registered in CDP corresponds to a single VPC located in a specific region, and all the resources deployed by CDP on AWS are deployed into that VPC. Therefore prior to registering an environment, you should decide which region you would like to use.
Typically, you may want to deploy clusters into the same region that contains the S3 buckets that you want to access for input and output data. Therefore, when selecting the region to use, you should consider where your data is located. Furthermore, CDP requires that the S3 storage location provided during environment registration is in the same region as the region selected for the environment.
If you need to use multiple regions, you need to register multiple environments, one per region.