Account:
- Root user login is tied to us-east-1 (during a us-east-1 outage, root user logins were broken) link
CloudFront:
- ACM certs must exist in us-east-1 for CloudFront to use them link
- Lambda functions used for Lambda@Edge must be deployed in us-east-1 link
- Control plane is only available in us-east-1 link
CloudTrial:
- For most global services, events are logged as occurring in us-east-1 link
CloudWatch:
- CloudWatch Billing metric data is stored in the US East (N. Virginia) Region and represents worldwide charges" link
IAM:
- Control plane is only available in us-east-1 link
Route53
- Control plane is only available in us-east-1 link
CloudWatch: "Billing metric data is stored in the US East (N. Virginia) Region and represents worldwide charges." link
Not sure how this would be impacted by an outage. If CloudWatch Metrics were not available in us-east-1, then I assume billing metrics would be inaccessible.