Amazon Aurora with PostgreSQL Compatibility supports data import from Amazon S3 in AWS GovCloud (US) Regions
Amazon Aurora with PostgreSQL compatibility now supports importing data stored in Amazon Simple Storage Service (S3) buckets to PostgreSQL tables in AWS GovCloud (US) Regions. A new extension, aws_s3, has been added to perform the import operation. You can import any data format that is supported by the PostgreSQL COPY command, using the ARN role association method or using Amazon S3 credentials.
Source:: Amazon AWS