App Engine is regional, which means the infrastructure that runs your apps is located in a specific region and is managed by Google to be redundantly available across all the zones within that region.
Meeting your latency, availability, or durability requirements are primary factors for selecting the region where your apps are run. You can generally select the region nearest to your app's users but you should consider the location of the other Google Cloud products and services that are used by your app. Using services across multiple locations can affect your app's latency as well as pricing.
App Engine is available in the following regions:
You cannot change an app's region after you set it.
If you already created an App Engine application, you can view the region by doing either of the following:
gcloud app describecommand.
Open the App Engine Dashboard in the Cloud Console. The region appears near the top of the page.
To select a region, you create an App Engine application in your Cloud project. See Managing Projects, Applications, and Billing for details in your language for either the standard or flexible environment.