AWS Direct Connect support for AWS Transit Gateway is now available in Asia Pacific (Mumbai), Asia Pacific (Seoul), Asia Pacific (Singapore), Asia Pacific (Tokyo), EU (Paris), and South America (Sao Paulo) regions. With this feature, customers can connect thousands of Amazon Virtual Private Clouds (Amazon VPCs) in multiple AWS Regions to their on-premises networks using 1/2/5/10 Gbps AWS Direct Connect connections.  

from Recent Announcements https://aws.amazon.com/about-aws/whats-new/2019/09/aws-direct-connect-support-for-aws-transit-gateway-is-now-available-in-six-additional-regions/