AWS GovCloud (US)
User Guide

Controlling Access to Your AWS GovCloud (US) Account

Your AWS GovCloud (US) account credentials grant full access to your AWS GovCloud (US) account. We recommend that you don't share your account credentials. Instead, use AWS Identity and Access Management (IAM) to grant users access to AWS GovCloud (US). With IAM, you can control who can perform which actions on a specific resource. Signing Up for AWS GovCloud (US) discusses how you create your first IAM administrative user.

For more information, see What Is IAM? in Using IAM.

For suggestions about how to secure your account with IAM, see IAM Best Practices in Using IAM.