In App Platform, the application is located in the region where you create the app in. However, App Platform uses the Cloudflare CDN, headquartered in the US, to provide domain configurations for apps. This means that when you lookup the IP of your app, you are seeing the IP address of the CDN’s load balancer and Anycast network. This does not mean your traffic is being routed through the US, though.
To check the IP address of your app, you can run the following from within the app’s console:
dig +short myip.opendns.com @resolver1.opendns.com
The IP output is the dynamic public IP address of your app. Unlike a static IP address, this address can change.