AWS Transit Gateway now supports the ability to establish peering connections between Transit Gateways in both AWS GovCloud (US) Regions. Transit Gateway is a service that enables customers to connect thousands of Amazon Virtual Private Clouds (Amazon VPCs) and their on-premises networks using a single gateway. With AWS Transit Gateway, customers only have to create and manage a single connection from a central regional gateway to each Amazon VPC, on-premises data center, or remote office across their networks.
Source:: Amazon AWS