The Lambda functions have to be configured in us-east-1, but they don't actually run there - they get replicated to the Cloudfront POPs you're using. e.g. we s

The Lambda functions have to be configured in us-east-1, but they don't actually run there - they get replicated to the Cloudfront POPs you're using. e.g. we set up our L@E functions in us-east-1, run our actual systems in eu-west-1, but 95%+ of our traffic comes in via eu-west-2, and the L@E functions output logs for that traffic to the eu-west-2 CloudWatch. For Cloudfront stuff, it's not very region dependent.